Let X denote the block rate of the host hotel for a particular conference, and let Y denote the lowest room rate available in the host hotel outside of the conference block. For a conference that requires a two-night hotel stay, which one of the following expressions represents the least amount of discount on the conference registration fee that, according to the article, would be sufficient to deter conference attendees from employing the ROB strategy in choosing accommodations?
A. X+Y2X+Y2
B. X−Y2X−Y2
C. X−YX−Y
D. X+YX+Y
E. 2(X−Y)

Answers

Answer 1

Answer:

C. X-Y X-Y

Step-by-step explanation:

The question asks to identify the least amount of discount on the conference registration. If the registration discount is at least half of the possible saving of ROB then all attendees will stay within the block. X is the block rate and Y is the non block rate. The saving for staying two nights outside the block is 2 (X-Y)


Related Questions

In the figure below, triangle DOG, triangle ION, and triangle IDO are congruent and isosceles, each with perimeter 55. The quadrilaterals FLIN, DIES, and DRAG are all squares. The perimeter of the 11-sided polygon $DRAGONFLIES$ is 127. What is the area of DRAG?

Answers

Answer:

81 sq units.

Step-by-step explanation:

Given that Triangles DOG, ION and IDO are congruent and isosceles.

Let Sides NO = IO = DO = GO = [tex]x[/tex] units

Let the sides of squares FLIN, DIES and DRAG = [tex]a[/tex] units

So, NF = FL = LI = NI = IE = ES = SD = DI = DR = RA = AG = GD = [tex]a[/tex] units

Given that perimeter of each of Triangles DOG, ION and IDO = 55 units

Sum of sides of triangle = [tex]2x+a=55 ...... (1)[/tex]

and Perimeter of 11 sided polygon DRAGONFLIES = 127 units

The perimeter of the polygon includes the sides (only outer sides are included):

DR, RA, AG, GO, ON, NF, FL, LI, IE, ES and SD

[tex]2x+9a = 127......(2)[/tex]

Solving equations (2) and (1) by subtracting (1) from equation (2):

[tex]8a = 72\\\Rightarrow a = 9 units[/tex]

Area of a square DRAG = [tex]Side^2[/tex] = [tex]9^2 = \bold{81\ sq\ units}[/tex]

Answer:

81

Step-by-step explanation:

dont ask, i just know

find the Perimeter Of a circle whose radius is 14cm​

Answers

Answer:

88 cm

Step-by-step explanation:

Perimeter = 2πr

=2(14)(22/7)

= 88 cm

Answer:

87.97cm

Step-by-step explanation:

This question is asking to solve for the circumference.

The formula for the circumference of a circle is:  [tex]\pi*diameter[/tex]

To work this out you would first need to multiply the radius of 14 by 2, this gives you 28cm. This is because the radius is half of the diameter.

The final step is to multiply pi by the diameter of 28, this gives you 87.97cm (87.9645943). This is because the formula for the circumference of a circle is [tex]\pi * diameter[/tex].

1) Multiply 14 by 2.

[tex]14*2=28[/tex]

2) Multiply pi by the diameter.

[tex]\pi*28^2=87.97 cm[/tex]

solution for 2x is equal to 10​

Answers

Answer:

The answer is 5

Step-by-step explanation:

divide 10 by two and get 5

Answer:

[tex]x = 5[/tex]

Step-by-step explanation:

We have the equation [tex]2x = 10[/tex], we can try and isolate x by dividing both sides by 2.

[tex]2x \div 2 = 10\div2\\x = 5[/tex]

Hope this helped!

The pair of figures is similar. Find x. Round to the nearest tenth if necessary.

Answers

Answer:

x ≈ 4.125 ft

Step-by-step explanation:

Since the figures are similar then the ratios of corresponding sides are equal, that is

[tex]\frac{11}{x}[/tex] = [tex]\frac{8}{3}[/tex] ( cross- multiply )

8x = 33 ( divide both sides by 8 )

x = 4.125 ft

Your fixed expenses are $1,235. 78/month. You want to save 5 months' worth for an emergency
fund over a year's time. How much must you save each month?

Answers

Answer:

  $514.91

Step-by-step explanation:

You want to save a total of ...

  5 × $1235.78

You want to do this over a 12-month period. So, you want to save 1/12 of this total each month. The amount you're saving each month is ...

  5(1235.78)/12 = 514.908333... ≈ 514.91

You must save $514.91 each month to reach the goal.

Answer: $514.91

Step-by-step explanation:

($1,235.78)(5 months)=$6,178.90


6,178.90/12 months=$514.91


(just for clarity: the other person is right, just wanted to show a simpler way to achieve the answer. gl :)

Lucy reads 450 words in 3 minutes.
This is an equation that can be used to
find w, the number of words Lucy can
read in 20 minutes if she continues to
read at the same rate?

Answers

Answer:

3000 words

Step-by-step explanation:

450 words in 3 minutes is 150 words in 1 minute. 20 minutes = 1 times 20.          

1 minute = 150 words so 150 words times 20 minutes = 3000 words.

use the formula S = 40,000 (1.06)t to calculate your salary after 4 years. Round your answer to the nearest dollar.



a. $42,400


b. $44,944


c. $47,641


d. $50,499

Answers

Answer:

d. $50,499

Step-by-step explanation:

Given:

S = 40,000 (1.06)^t

Where,

t=4 years

S=40,000(1.06)^4

=40,000(1.26247696)

=50,499.0784

To the nearest dollar

S=$50,499

The answer is d. $50,499

The temperature in Anchorage, Alaska at 6:00 am was 2°C. If the temperature drops 2 degrees each hour, what is the temperature in degrees celsius at 2:00 pm

Answers

Answer:

-12°C

Step-by-step explanation:

6AM = 2°C

8AM= -2°C

10AM= -6°C

12AM= -8°C

2PM= -12°C

the temperature in degrees Celsius at 2:00 pm would be -14°C.

To find the temperature in degrees Celsius at 2:00 pm, we need to determine the number of hours that have passed from 6:00 am to 2:00 pm, and then calculate the temperature decrease accordingly.

From 6:00 am to 2:00 pm, a total of 8 hours have passed (6 hours from 6:00 am to 12:00 pm, and 2 hours from 12:00 pm to 2:00 pm).

Given that the temperature drops 2 degrees Celsius each hour, we can multiply the number of hours (8) by the rate of temperature decrease (2 degrees/hour):

Temperature decrease = 8 hours × 2 degrees/hour = 16 degrees

Starting with a temperature of 2°C at 6:00 am, if the temperature drops 16 degrees Celsius over 8 hours, we can subtract 16 from the initial temperature:

Temperature at 2:00 pm = 2°C - 16°C = -14°C

Therefore, the temperature in degrees Celsius at 2:00 pm would be -14°C.

Learn more about temperature here

https://brainly.com/question/29197322

#SPJ2

The price of tiling a room varies directly as the size of the room. Sam is laying tile in his kitchen. If the tiling costs $4,224.00 for 264 square feet, what is the size of a kitchen that costs $3,824.00? A. 239 square feet B. 256 square feet C. 7,648 square feet D. 63,096 square feet

Answers

Answer:

The answer is option A

Step-by-step explanation:

Let the price of the room be p

Let the size of the room be s

To find the size of a kitchen that costs $3,824.00 we must first find the relationship between them

The statement

The price of tiling a room varies directly as the size of the room is written as

p = ks

where k is the constant of proportionality

when

p = $4,224.00

s = 264 square feet

Substitute the values into the expression to find k

That's

4224 = 264k

Divide both sides by 264

k = 16

So the formula for the variation is

p = 16s

when

p = 3824

[tex]s = \frac{p}{16} [/tex]

[tex]s = \frac{3824}{16} [/tex]

s = 239

The final answer is

239 square feet

Hope this helps you

What is the LCD for x/4 - 2/3 = 7/12?

Answers

Answer:

12

Step-by-step explanation:

All the denominators are factors of 12.

Sandra spotted the sailboat from the shore and measured the angle from the waterline to the top of the boats mast to be 7° if the top of the mask is 23 feet above the water how far is the middle of the sailboat from the shore? Estimate your answer to the nearest tenth.

Answers

Answer:

The middle of the sailboat is approximately 268.8 feet from the shore.

Step-by-step explanation:

Let the distance from shore to the middle of the boat be represented by x, the angle of elevation of Sandra from the shore to the top of the boat mast  is 7°. Applying the required trigonometric function to this question, we have;

Tan θ = [tex]\frac{opposite}{adjacent}[/tex]

Tan 7° = [tex]\frac{23}{x}[/tex]

⇒  x = [tex]\frac{23}{Tan 7^{0} }[/tex]

       = [tex]\frac{23}{0.12279}[/tex]

      = 268.7515

∴ x = 268.8 feet

The middle of the sailboat is approximately 268.8 feet from the shore.

The point-slope form of the equation of the line that passes through points (-5,-1) and (10, -7 ) is y-4=1/4 (x-8) what is the slope intercept form of the equation for this line​ ?

Answers

Answer:

y = [tex]\frac{1}{4}[/tex] x + 2

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Given

y - 4 = [tex]\frac{1}{4}[/tex] (x - 8) ← distribute

y - 4 = [tex]\frac{1}4}[/tex] x - 2 ( add 4 to both sides )

y = [tex]\frac{1}{4}[/tex] x + 2 ← in slope- intercept form

how do i solve this ?(x+3)(x-5)=

Answers

[tex](x+3)(x-5)=x^2-5x+3x-15=x^2-2x-15[/tex]

Answer:

Step-by-step explanation:

Use FOIL method

(x + 3)(x - 5) = x*x  + x *(-5)  + 3*x +  3*(-5)

                    = x² - 5x  +3x - 15  {add like terms}

                    = x² - 2x -15

Which number is in the 3rd position after ordering in
descending order. V220,-10, V100, 11.5

Answers

Answer:

√100

Step-by-step explanation:

Given the following numbers: √220, -10, √100, 11.5,

Let's arrange the numbers from the largest to the smallest (in descending order).

Note: √220 ≈ 14.8

√100 = 10

From the largest to the smallest number, we have: √220, 11.5, √100, -10

Therefore, the number in the third position is √100

the sum of 48 and itself its half and half of the hal is added to 18​

Answers

Answer:

150

Step-by-step explanation:

We are carrying out Addition

a) The sum of 48 and itself

= 48 + 48 = 96

b) Its half and half of the half

96 + (1/2 × 48) + (1/2 ×( 1/2 × 48)

= 96 + 24 +(1/2 × 24)

= 96 + 24 + 12

= 132

c) is added to 18

= 132 + 18

= 150

Therefore, the sum of 48 and itself, its half and half of the half is added to 18 is 150

The sum of 48 and itself its half and half of the half is added to 18​ is 150.

Given, we have a number 48.

We have to find the sum of 48 and itself its half and half of the half is added to 18​.

So, the half of the 48 is 24 and half of the half becomes 12.

Now the equation becomes,

[tex]48+48+24+12+18=150[/tex]

Hence the required sum is 150.

For more details follow the link:

https://brainly.com/question/2263981

5/8 divided by 11/9 divided by 1/4=

Answers

Answer:

45/22

Step-by-step explanation:

(a/b)/(c/d) = (a*d)/(b*c)

then

{(5/8)/(11/9)} / {1/4)}

= {(5*9)/(8*11)} / {1/4)

= {45/88} / {1/4}

= {45*4} / {88*1}

= 180/88

= 45 / 22

Simplify the expression a-2b, when a=1.4 - 2x and b=-0.2x + 1.7 *

Answers

Answer:

a-2b= -1.6x-2.0

Step-by-step explanation:

[tex]a=1.4-2x\\b=-0.2x+1.7\\a-2b= (1.4-2x)-2(-0.2x+1.7)\\a-2b= 1.4-2x+0.4x-3.4\\a-2b=-1.6x-2.0\\[/tex]

{By, substituting the values of a and b in a-2b , we can find the value of a-2b}

An empty row in a frequency table is a mistake True or false

Answers

Answer:

False I think

Step-by-step explanation:

Which is the simplified form of the expression ((2 Superscript negative 2 Baseline) (3 Superscript 4 Baseline)) Superscript negative 3 Baseline times ((2 Superscript negative 3 Baseline) (3 squared)) squared?

Answers

Answer:

[tex]\dfrac{1}{6561}[/tex]

Step-by-step explanation:

Given the expression [tex][(2^{-2})(3^{4})]^{-3} * [(2^{-3})(3^2)]^{2}[/tex], Using the laws of indices to simplify the expression. The following laws will be applicable;

[tex]a^m*a^n = a^{m+n}\\(a^m)^n = a^{mn}\\[/tex]

[tex]a^{-m} = 1/a^m[/tex]

Given [tex][(2^{-2})(3^{4})]^{-3} * [(2^{-3})(3^2)]^{2}[/tex]

open the parenthesis

[tex]= (2^{-2})^{-3}(3^{4})^{-3}* (2^{-3})^2(3^2)^2\\\\= 2^{-2*-3}* 3^{4*-3} * 2^{-3*2} * 3^{2*2}\\\\= 2^6 * 3^{-12} * 2^{-6} * 3^4\\\\collecting \ like \ terms\\\\= 2^6 * 2^{-6} * 3^{-12} * 3^4\\\\= 2^{6-6} * 3^{-12+4}\\\\= 2^0 * 3^{-8}\\\\= 1 * \frac{1}{3^8}\\ \\= \frac{1}{6561}[/tex]

What is the formula for finding mean or average?​

Answers

Answer:

LOOK BELOW

Step-by-step explanation:

I would not call the explanation a formula

All you have to do to solve mean or average is add all of the numbers up and divide by the total amount of numbers

so for example

0,2,4,0,2,3,2,8,6  <-------- lets find the mean/average

0+2+4+2+3+2+8+6= 27/amount of numbers

amount of numbers=9

(count the zeros too!)

27/9=3

3 is the mean or average!!!

What is the LCD of 1/2 and 3/5

Answers

Answer:

10

Step-by-step explanation:

How you find LCD (lowest common denominator) is that you have to look at the denominator (the bottom number) and try to find the lowest multiple between both of the numbers that is on the bottom (in this case it is 2 and 5). Sometimes you have to multiply both denominators together to get a LCD.

Example of multiplying two denominators together to get an LCD:

1/3 and 1/13 LCD is 39 because you multiply 3 and 13.

1/5 and 1/4 LCD is 20 because you multiply 5 and 4.

name four points that are not coplanar​

Answers

Answer: U, W, Z and Y

Step-by-step explanation:

4 points are not coplanar if there does not exist any plane that contains the 4 points.

So, a plane is formed by a line and one point outside of it.

Then, we want to select the last point in such a way that it lies outside of the plane generated by the first 3 points selected.

For example:

If first we select Point U and Point W, we will have a line, as shown in the image.

Now we can select the Point  Z, that is outside the line, and now we have the plane M that you can see in the image.

Now we need to select a point that is not in the plane, the only two options are Point X and Point Y, we can select any of those two, let's take the Point Y.

So, here we have that:

Points U, W, Z and Y are not coplanar.

Please someone help ASAP!!!!!!

Answers

Answer:

1.7 million in Northern Ireland

Step-by-step explanation:

Simply do the difference between the number of people in the UK, minus the number of people in everywhere else except northern Ireland. That is:

60.2 M - 50.4 M - 5.1 M - 3.0 M = 1.7 M

Answer:

[tex]\boxed{1.7 million}[/tex]

Step-by-step explanation:

Hey there!

To find the amount of people who lived in Northern Ireland in 2005 we need to subtract the total 60.2 mil by the England, Scotland, and Wales people.

50.4 + 5.1 + 3

= 58.5

Now we can set up the following equation,

NI = 60.2 - 58.5

NI = 1.7 million

Hope this helps :)

Kyle stood on a bridge and threw a rock up and over the side. The height of the rocks in meters can be approximated by approximated by -5t^2+5t+24, where T is the time in seconds after car through it completely factor the expression

Answers

Answer:

The factorized expression is (-5) × (t - 2.747) ×(t - 1.747)

Step-by-step explanation:

The given expression is -5·t² + 5·t + 24

To factorize the expression by completing the square method, we equate the expression to zero to get;

-5·t² + 5·t + 24 = 0

WE divide by -5 to get;

t² - t - 24/5 = 0

t² - t = 24/5

t² - t + 1/4 = 24/5 + 1/4

(t - 1/2)² = 5.05

t - 1/2 = ±√5.05

t = 1/2 + √5.05, 1/2 - √5.05

The factorized expression becomes;

(t - 1/2 + √5.05) and (t - 1/2 - √5.05)

Which gives;

(t - 2.747) ×(t - 1.747)

The factorized expression is (-5) × (t - 2.747) ×(t - 1.747).

An ant needs to travel along a 20cm × 20cm cube to get from point A to point B. What is the shortest path he can take, and how long will it be (in cm)?

Answers

Each edge of the cube is 20cm. If it stayed on the edges it would need to walk on 3 edges for a total distance of 3 x 20 = 60 cm.

If it walked diagonally across the front face and then one edge it would travel:

Diagonal = sqrt(20^2 + 20^2) = 28.28

Total distance waling a diagonal and then an edge = 28.28 + 20 = 48.28 cm

The shortest distance would be diagonally across the front face then the edge to point B and the distance would be 48.28 cm.

f(x) = x+ bx + 5 In the given function, b is a constant. If f(1) = 0, what is the value of f(3) ?

Answers

Answer:

f(x)= x+bx+5

f(1) = 1+ b(1) +5 =0

f(1) = 6 +b =0

6+b=0

b=-6

so we get,

f(3)= 3 -6(3)+5

f(3) = 3-18+5

f(3) = -10

hope it helps ^°^

A street light is at the top of a 15 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 6 ft/sec along a straight path. How fast is the length of her shadow increasing when she is 50 ft from the base of the pole

Answers

Answer:

4 ft/sec

Step-by-step explanation:

Hope it helps

A certain forest covers an area of 2600 km^2. Suppose that each year this area decreases by 4.75%. What will the area be after 11 years? Use the calculator provided and round your answer to the nearest square kilometer.

Answers

Answer:

1522km^2

Step-by-step explanation:

To solve this, first convert the percentage to a decimal. That would be .0475.

Now subtract that from 1.0 to get the factor it decreases by. This would be 1-.0475 = .9525

Multiply 2600 x (.9525)^11 = 1522.258 which rounds to 1522 km^2

Answer:

The area will be 1292.98 km² after 11 years.

Step-by-step explanation:

To find what decreases by 4.57% each year in kilometers:

2600 × 4.57/100 = 26 × 4.57

= 118.82 km²

To find the area after 11 years:

118.82 × 11 = 1307.02

2600 - 1307.02 = 1292.98 km²

1292.98 km² is the answer.

Combine like terms to simplify the expression: -5.55-8.55c+4.35c

Answers

Answer:

-5.55 - 4.2c

Step-by-step explanation:

-5.55 - 8.55c + 4.35c

'-8.55c' and '4.35c' are like terms because of them containing the same variable of 'c'.

Combine:

-5.55 - 8.55c + 4.35c

-8.55 + 4.35 = -4.2

-5.55 - 4.2c

Hope this helps.

Select the correct answer. The velocity of a train relative to the ground is represented by the distance from A to B in the diagram. The velocity of a ball thrown inside the train at an angle of 66° relative to the train is represented by the distance from B to C. What is the distance from A to C (the velocity of the ball relative to the ground), correct to two decimal places? Assume that all the points in the diagram lie in the same plane. A. 21.14 m/s B. 18.03 m/s C. 17.20 m/s D. 15.00 m/s

Answers

Answer:

Step-by-step explanation:

we use cosine formula

2×15×10×cos(180-66)=15²+10²-AC²

-300 cos 66=225+100-AC²

AC²=325+300 cos 66

[tex]AC=\sqrt{325+300 cos 66} \approx 21.14 ~m/s[/tex]

The distance from A to C is 21.14. The correct option is A.

What is trigonometry?

Trigonometry is the branch of mathematics which set up a relationship between the sides and angles of right-angle triangles.

Velocity is defined as the ratio of the distance moved by the object at a particular time. The velocity is a vector quantity so it needs both the magnitude and the direction.

Given that the velocity of a train relative to the ground is represented by the distance from A to B in the diagram. The velocity of a ball thrown inside the train at an angle of 66° relative to the train is represented by the distance from B to C.

The distance A to C will be calculated as,

2×15×10×cos(180-66)=15²+10²-AC²

-300 cos 66=225+100-AC²

AC=√(325+300 cos 66)

AC = 21.17 m/s

Therefore, the distance from A to C is 21.14. The correct option is A.

To know more about trigonometry follow

https://brainly.com/question/14931414

#SPJ3

Other Questions
How many digits of pi does it take to add up to 14, 25, 68, 103, and 150? I am being timed, whoever answers this fast or quick I will give you the brainiest!!!PLEASE HELP QUICK y=-2x+4 missing value Give this problem a try and try to solve this Low self esteem may lead to _______ on parents, which makes children rely on parents even for unimportant decisions How do mutations affect the production of proteins in our bodies? An electron is trapped between two large parallel charged plates of a capacitive system. The plates are separated by a distance of 1 cm and there is vacuum in the region between the plates. The electron is initially found midway between the plates with a kinetic energy of 11.2 eV and with its velocity directed toward the negative plate. How close to the negative plate will the electron get if the potential difference between the plates is 100 V? (1 eV = 1.6 x 10-19 J) IOP Company purchased a machine on 1/1/22 costing $500. Estimated life was 5 years; estimated salvage value was $100. In 2025, IOP discovered that the bookkeeper correctly used straight-line depreciation, but erroneously used an estimated life of 8 years in computing depreciation for the first 3 years of life. The Prior Period Adjustment to be recorded in 2025 will be: please help please give ans in points at least five points please help!!!write about the impact of French revolution on the world ORwhat did French revolution introduced the world Read the excerpt from Tools of the Spymaster."The numbers that Major Tallmadge assigned to members of the Culper Ring were from a secret writing system he invented. He substituted digits for words that would be used in messages. "Long Island," for example, was 728, "arms" was 7, and "city" was 88. There was a number for each month, such as 341 for "January." He made four copies of his codes. He kept one and gave the others to Woodhull, Townsend, and General Washington. For words that did not have a number code, Tallmadge gave his agents a cipher. In a cipher, each letter in a message is replaced by another letter or a number.Which statement is best supported by text evidence from the excerpt?All members of the Culper Ring received a copy of Tallmadges code.A cipher was a common instrument used during the American Revolution.Words that did not have a number code could not be used in secret messages.General Washington could read messages written in Tallmadges code. What is the scale factor of abc to def In using cloud infrastructures, the client necessarily cedes control to the CP on a number of issues that may affect securitya. Trueb. False Roybus, Inc., a manufacturer of flash memory, just reported that its main production facility in Taiwan was destroyed in a fire. Although the plant was fully insured, the loss of production will decrease Roybus's free cash flow by $175 million at the end of this year and by $61 million at the end of next year. a. If Roybus has 37 million shares outstanding and a weighted average cost of capital of 12.6%, what change in Roybus's stock price would you expect upon this announcement? (Assume that the value of Roybus's debt is not affected by the event.) b. Would you expect to be able to sell Roybus stock on hearing this announcement and make a profit? Explain. When Samuel Johnson coined the term metaphysical poets, what trait was he calling attention to? A. the poets incorporation of nature imagery B. the poets redefinition of euphonic sounds C. the poets fondness for abstract ideas D. the poets interest in philosophical questions I need help with this question. PLZZ HELP!!! In the three As of security, which part pertains to describing what the user account does or doesn't have access to Simplify the following expression -10x + 10x A young sumo wrestler decided to go on a special high-protein diet to gain weight rapidly. When he started his diet, he weighed 79.5 kilograms. He gained weight at a rate of 5.5 kilograms per month. Let y represent the sumo wrestler's weight (in kilograms) after x months. Which of the following could be the graph of the relationship? graph of an increasing linear function in quadrant 1 with a positive y-intercept (Choice B) B graph of an increasing linear function in quadrants 1 and 4 with a positive x-intercept and negative y-intercept (Choice C) C graph of a decreasing linear function in quadrants 1 and 4 with a positive x-intercept and positive y-intercept (Choice D) D graph of a decreasing linear function in quadrant 4 with a negative y-intercept One researcher wishes to estimate the mean number of hours that high school students spend watching TV on a weekday. A margin of error of 0.28 hour is desired. Past studies suggest that a population standard deviation of hours is reasonable. Estimate the minimum sample size required to estimate the population mean with the stated accuracy. Ned is trying to decide how he wants to connect the nodes on the network he created. What are the two options that he has?Select one:a through physical nearness or a central serverb. through hard cabling or wireless radio wavesc. through ethernet cables or Bluetoothd. through software programs or osmosis Can you help me find all the seventh roots of unity? what do they look like graphed?