Let R be a system consisting of rational expressions. Which operations are closed for R?

Answer: There are 15 friends.

Step-by-step explanation:

We know that there is N friends (N is the number that we are looking for)

Each friend weights 1/20 ton.

Now, the weight of the N friends together is N times 1/20 ton.

Then we have:

N*(1/20) ton = 3/4 ton

We solve this for N.

First multiply both sides by 20.

20*N*(1/20) = N = 20*(3/4) = 60/4 = 15

Answer:

I can find the total number of people by dividing the total weight by the weight of one person.

Step-by-step explanation:

Answer:

red

Step-by-step explanation:

Since the bag contains more red marbles than any other color, you are most likely to pick a red marble

Answer:

[tex]71,100[/tex]

Step-by-step explanation:

If you are trying to find a number that is written in word form, we can just use place values to find what goes where.

A number is broken down into this:

Ten thousands, thousands, hundreds, tens, ones.

If they have 7 ten thousands, the first digit will be a 7.

If they have 1 thousand, the second digit will be a 1.

If they have 1 hundred, the third digit will be a 1.

Since nothing is stated about tens, we assume it's value is 0.

And since there are no ones, it's value is 0.

So:

71,100.

Hope this helped!

Answer:

the margin of error

= 1.96 x 0.0632

= 0.124

Step-by-step explanation:

this question has the sample size, n = 40

8 people have received help from their parents from this sample.

8/40 = 0.2

which is the sample proportion

z = 1 - 0.2

= 0.8

to calculate standard error

√pz/n

= √0.2 x 0.8/40

= √0.16/40

= 0.0632

at 95% confidence level

z(alpha/2) = 1.96

therefore the margin of error

= 1.96 x 0.0632

= 0.124

Answer:

The first pyramid:

      63x

  39x  24x  

23x  16x  8x

The second pyramid:

     162x

 82x  80x  

4x  78x  2x

The third pyramid:

     12a+2b

9a+b   3a+b  

9a     b     3a

The fourth pyramid:

      -19a

  -5a   -14a  

3a   -8a  -6a

Step-by-step explanation:

All that an alegbra pyramid is is adding the two terms below it.

So you can see how I added the terms that lied below each number, such as in number 1:  I added 23x and 16x to get me 39x, and I added 16x and 8x to get me 24.

Hope this helped!

Answer:

Suppose that the height (in centimeters) of a candle is a linear function of

the amount of time (in hours) it has been burning.

After 11 hours of burning, a candle has a height of 23.4 centimeters.

After 30 hours of burning, its height is 12 centimeters.

What is the height of the candle after 13 hours?

:

Assign the given values as follows:

x1 = 11; y1 = 23.4

x2 = 30; y2 = 12

:

Find the slope using: m = %28y2-y1%29%2F%28x2-x1%29

m = %2812-23.4%29%2F%2830-11%29 = %28-11.4%29%2F19

:

Find the equation using the point/slope formula: y - y1 = m(x - x1)

y - 23.4 = -11.4%2F19(x - 11)

y - 23.4 = -11.4%2F19x + 125.4%2F19

y = -11.4%2F19x + 125.4%2F19 + 23.4

y = -11.4%2F19x + 125.4%2F19 + 23.4

y = -11.4%2F19x + 125.4%2F19 + 444.6%2F19

y = -11.4%2F19x + 570%2F19

y = -11.4%2F19x + 30, is the equation

:

What is the height of the candle after 13 hours?

x = 13

y = -11.4%2F19(13) + 30

y = -148.2%2F19 + 30

y = -7.8 + 30

y = 22.2 cm after 13 hrs

Answer:

A - 3.3%

Step-by-step explanation:

From the graph

Where x= 0

Amount =$ 450

It shows that$450 is the capital

Then

When x= 3

Amount=$494.55

So interest generated within 3 years

= $494.55-$450

=$ 44.55

When x= 9

Amount = $583.65

So interest generated within 9 years

= $583.65-$450

=$ 133.65

PRT/10= Interest

450*x*3/100= 44.55

1350x= 4455

X= 4455/1350

X= 3.3

So the rate is =3.3%

Answer:

a) The company sold 93 Chicken dinners, 76 Beef dinners and 31 Fish dinners.

b) [tex]y=3x^{2}-4x+2[/tex]

Step-by-step explanation:

a)

In order to solve part a of the problem, we must start by setting our variables up:

C=# of Chicken dinners

B=# of Beef dinners

F=# of Fish dinners

Next we can use these variables to build our equations. We start by taking the fact that they sold a total of 200 dinners. The sum of all the variables should add up to that so we get:

C+B+F=200

Then the problem tells us the price of each dinner and the total amount of money they made from selling the dinners that day:

"A TV Dinner Company Sells Three Types Of Dinners: A Chicken Dinner For $10, A Beef Dinner For $11, Or A Fish Dinner For $12. For A Grand Total Of $2138"

So we can use this information to build our second equation:

10C+11B+12F=2138

We have two equations now but three variables, so we need an additional equation so we can finish solving this. The problem tells us that:

"they sold three times as many chicken dinners as they did fish"

which translates to:

C=3F

so now we have enough information to finish solving the problem. We can start by substituting the last equation into the previous two equations so we get:

C+B+F=200

3F+B+F=200

4F+B=200

and

10C+11B+12F=2138

10(3F)+11B+12F=2138

30F+11B+12F=2138

42F+11B=2138

So now we can take the two bolded equations and solve them simultaneously. We can solve them by using any method we wish. Let's solve it by substitution.

We start by solving the first equation for B so we get:

B=200-4F

and now we substitute it into the second equation:

42F+11(200-4F)=2138

and now we solve for F

42F+11(200-4F)=2138

42F+2200-44F=2138

-2F=2138-2200

[tex]F=\frac{-62}{-2}[/tex]

F=31

So now that we know the value of F, we can find the values of the rest of the variables so we can take the previous equations to figure this out:

B=200-4F

B=200-4(31)

B=200-124

B=76

and finally:

C=3F

C=3(31)

C=93

So

The company sold 93 Chicken dinners, 76 Beef dinners and 31 Fish dinners.

b) For the second part of the problem we need to build a system of equations to find the equation we are looking for. We were given three points:

(-1,9), (2,6) and (3,17)

so we need to substitute each of the points on the given quadratic equation so we get:

[tex]9=a(-1)^{2}+b(-1)+c[/tex]

eq.1:  [tex]9=a-b+c[/tex]

[tex]6=a(2)^{2}+b(2)+c[/tex]

eq. 2:  [tex]6=4a+2b+c[/tex]

[tex]17=a(3)^{2}+b(3)+c[/tex]

eq. 3:  [tex]17=9a+3b+c[/tex]

So now that we have our three equations we can solve them simultaneously to get the values of a, b and c by using the method you feel more comfortable with. Let's solve it by elimination:

So let's take the first equations and let's subtract them:

[tex]9=a-b+c[/tex]

[tex]-6=-4a-2b-c[/tex]

-------------------------------

3=-3a-3b

And now we repeat the process with the first and third equations:

[tex]9=a-b+c[/tex]

[tex]-17=-9a-3b-c[/tex]

-------------------------------

-8=-8a-4b

So now we have two new equations we can solve simultaneously, but they can be simplified by dividing the first one into -3 and the second one into -4 so they become:

a+b=-1

2a+b=2

We can now solve them by substitution. Let's solve the first one for a and then let's substitute it into the second equation:

a=-1-b

let's substitute

2(-1-b)+b=2

and solve for b

-2-2b+b=2

-b=4

b=-4

Now we can find a:

a=-1-b

a=-1+4

a=3

and now we can find c:

c=9-a+b

c=9-3-4

c=2

So we can use these answers to build our equation:

[tex]y=ax^{2}+bx+c[/tex]

[tex]y=3x^{2}-4x+2[/tex]

Answer:

$24

Step-by-step explanation:

You simply do $42-$18

=24

Answer:

$24

Step-by-step explanation:

At the start, Jaime had $42. In order to find out how much the T-shirt he purchased costs, we must subtract 18 from 42.

42 - 18 = 24

Jaime spent $24 on the T-shirt.

Answer:

L ≈ 1023.0562

Step-by-step explanation:

We are given;

x = t² - 2t

dx/dt = 2t - 2

Also, y = t^(5)

dy/dt = 5t⁴

The arc length formula is;

L = (α,β)∫√[(dx/dt)² + (dy/dt)²]dt

Where α and β are the boundary points. Thus, applying this to our question, we have;

L = (1,4)∫√[(2t - 2)² + (5t⁴)²]dt

L = (1,4)∫√[4t² - 8t + 4 + 25t^(8)]dt

L = (1,4)∫√[25t^(8) + 4t² - 8t + 4]dt

Using online integral calculator, we have;

L ≈ 1023.0562

The length of the curve is 1023.0562 and this can be determined by doing the integration using the calculator.

Given :

First, differentiate x and y with respect to 't'.

[tex]\rm \dfrac{dx}{dt}=2t-2[/tex]

[tex]\rm \dfrac{dy}{dt}=5t^4[/tex]

Now, determine the length of the curve using the below formula:

[tex]\rm L = \int^b_a\sqrt{\left(\dfrac{dx}{dt}\right)^2+\left(\dfrac{dy}{dt}\right)^2} dt[/tex]

Now, substitute the value of the known terms in the above formula and then integrate it.

[tex]\rm L = \int^4_1\sqrt{(2t-2)^2+(5t^4)^2} dt[/tex]

[tex]\rm L = \int^4_1\sqrt{25t^8+4t^2-8t+4} \;dt[/tex]

Now, simplify the above integration using the calculator.

L = 1023.0562

For more information, refer to the link given below:

https://brainly.com/question/18651211

Answer:

y - 3 = -1/2(x - 1)

Step-by-step explanation:

Hey there!

Well point slope form is,

[tex]y - y_{1} = m(x - x_{1})[/tex]

We can use the point (1,3)

y - 3 = m(x - 1)

Now we need to find slope with the following formula,

[tex]\frac{y^2-y^1}{x^2-x^1}[/tex], we’ll use the points (1,3) and (5,1).

[tex]\frac{1-3}{5-1}[/tex]

-2/4

Slope or m = -1/2

y - 3 = -1/2(x - 1)

Hope this helps :)

Answer:

x= -20

Step-by-step explanation:

x/2=3x/4+5

Multiply both sides of the equation by 4, the least common multiple of 2,4.

2x=3x+20

Subtract 3x from both sides.

2x−3x=20

Combine 2x and −3x to get −x.

−x=20

Multiply both sides by −1.

x=−20

Answer:

(3 1/2, -4)

Step-by-step explanation:

The solution is the point on the graph that the two lines intersect.  The point that the lines intersect in the graph is (3 1/2, -4).

Answer:

3 1/2 , -4

Step-by-step explanation:

yes

There will be a total of 4 test scores including the final exam. To get a 70, the 4 tests need to equal 4 x 70 = 280 points , to be 79, they have to equal 4 x 79 = 316 points.

The 3 already done = 61 + 62 + 86 = 209 points.

The final exam needs to be between :

280 -209 = 71

316 -209 = 107. The answer would be between 71 and 100%

Answer:

the area of a section of a circle is [tex]\frac{1}{360}[/tex]* Θ * (area of the circle)

the theta/360 tells us the amount of circle currently in question

so , the answer will be 1/3 pi r^2        [A]

Answer: The triangles are not congruent

==========================================

Explanation:

For triangle DEF, the missing angle D is

D+E+F = 180

D+80+60 = 180

D+140 = 180

D = 180-140

D = 40

While the missing angle K in triangle JKL is

J+K+L = 180

80+K+50 = 180

K+130 = 180

K = 180-130

K = 50

---------------------

The three angles for triangle DEF are

The three angles for triangle JKL are

We don't have all the angles matching up. We need to have the same three numbers (the order doesn't matter) show up for both triangles in order for the triangles to be congruent. This is because congruent triangles have congruent corresponding angles.

The only pair that matches is E = 80 and J = 80, but everything else is different. So there is no way the triangles are congruent.

Notice how triangle JKL has two congruent base angles (K = 50 and L = 50), so this triangle is isosceles. Triangle DEF is not isosceles as we have three different angles, so this triangle is scalene.

Answer:

3

Step-by-step explanation:

a is 4 and 3 is x so 4+3=7

Answer: a=2 {x=3} r=1.         2(3)+ 1= 7

Step-by-step explanation:

Answer:

Answer: y=23

Step-by-step explanation:

If Points and A,B and C lines on the same line then they will have the same slopes so since we have the coordinates of  A and B we will use the to write an equation in slope intercept form.

To write it in slope intercept form we will need to find the slope and the y intercept.

To find the slope you will find the change in the y coordinates and divide it by the change in the x coordinates.

Using the coordinates (-1,7) and (2,19)  the y coordinates are 7 and 19 and the x coordinates are -1 and 2.

Slope :  [tex]\frac{7-19}{-1-2} \frac{-12}{-3} = 4[/tex]   In this case the slope is 4 so we will use that to find the y intercept by using point A coordinate.

  The slope intercept formula says that y=mx +b  where me is the slope and b is the y intercept.

 7=4(-1) + b  

7 = -4 + b

+4   +4

 b= 11       The y intercept is 11.

Now we can write the whole equation as y=4x + 11   .

To answer the question now, where we need to find y , we will plot the x coordinate which is 3 into the equation and solve for y.

 y = 4(3) + 11  

y = 12 + 11

 y = 23

Answer:

The 95% confidence interval is   [tex]0.88 < \mu_1 - \mu_2 < 5.12[/tex]

Step-by-step explanation:

From the question we are told that

   The  sample mean for fat-blocking [tex]\= x_1 = 13.7[/tex]

     The  sample size  for fat-blocking  [tex]n = 12[/tex]

      The standard deviation for  fat-blocking is [tex]\sigma_1 = 2.6[/tex]

      The  sample mean for control group is  [tex]\= x _2 = 10.7[/tex]

      The  sample size  for control group is [tex]n_2 = 12[/tex]

      The standard deviation for control group is [tex]\sigma _2 = 2.4[/tex]

Given that the confidence level is  95% then the level of significance can me mathematically evaluated as

                 [tex]\alpha = 100 - 95[/tex]

                 [tex]\alpha = 5 \%[/tex]

                    [tex]\alpha =0.05[/tex]

Generally the degree of freedom is mathematically represented as

           [tex]df = n_1 + n_2 - 2[/tex]

substituting values

           [tex]df = 12 +12 - 2[/tex]

           [tex]df = 22[/tex]

Next we obtain the critical value of [tex]\frac{\alpha }{2}[/tex] at a degree of freedom of  22 form the students t-distribution , the value is  

                [tex]t_{\frac{\alpha }{2}, df } = 2.074[/tex]

Generally the margin of error is mathematically represented as

            [tex]E = t_{\frac{\alpha }{2}, df } * \sqrt{ \frac{\sigma^2_1 }{n_1 } + \frac{\sigma^2_2 }{n_2 } }[/tex]

substituting values

            [tex]E = 2.07 4 * \sqrt{ \frac{ 2.6^2 }{12 } + \frac{2.4^2 }{12 } }[/tex]

           [tex]E = 2.12[/tex]

the 95% confidence interval for the differences of the means is mathematically represented as

        [tex]\= x_1 - \= x_2 - E < \mu_1 - \mu_2 < \= x_1 - \= x_2 + E[/tex]

substituting values

       [tex]13.7 - 10.7 - 2.12 < \mu_1 - \mu_2 < 13.7 - 10.7 + 2.12[/tex]

      [tex]0.88 < \mu_1 - \mu_2 < 5.12[/tex]

Answer:

An overdraft fee is a fee banks charge for withdrawing more money from an account than the current balance of that account. Banks charge overdraft fees to discourage overdrawing accounts and to make money from fees.

Step-by-step explanation:

Answer: Overdraft fee is when you withdraw more money from an account than the current balance of that account.

Step-by-step explanation:

Fees are charged to discourage overdrawing accounts and to make money from fees.

Answer:

[tex]\frac{4x+2}{x^2 - 9x + 8} = \frac{4x}{(x-8)(x-1)} + \frac{2}{(x-8)(x-1)}[/tex]

Step-by-step explanation:

Given

[tex]\frac{4x+2}{x^{2}-9+8 } = \frac{A}{()(x-1)} + \frac{B}{()(x-8)}[/tex]

Required

Fill in the gaps

Going by the given parameters, we have that

[tex]\frac{4x+2}{x^{2}-9+8 } = \frac{A}{()(x-1)} + \frac{B}{()(x-8)}[/tex]

[tex]x^2 - 9x + 8[/tex], when factorized is [tex](x-1)(x-8)[/tex]

Hence; the expression becomes

[tex]\frac{4x+2}{(x-1)(x-8)} = \frac{A}{(x-8)(x-1)} + \frac{B}{(x-1)(x-8)}[/tex]

Combine Fractions

[tex]\frac{4x+2}{(x-1)(x-8)} = \frac{A + B}{(x-8)(x-1)}[/tex]

Simplify the denominators

[tex]4x + 2 = A + B[/tex]

By direct comparison

[tex]A = 4x[/tex]

[tex]B = 2[/tex]

Hence, the complete expression is

[tex]\frac{4x+2}{x^2 - 9x + 8} = \frac{4x}{(x-8)(x-1)} + \frac{2}{(x-8)(x-1)}[/tex]

Answer:4x+2/x2−9x+8 = −6/7(x−1) + 34/7(x−8)

Answer:

D

Step-by-step explanation:

To determine the range we must solve this inequality;

● 1200000<1800000-250x<1300000

Substract 1800000 from both sides.

● 1200000-1800000<1800000-250x<1300000-1800000

● -600000< -250x < -500000

Divide both sides by 250

● -600000/250 < -250x/250 < -500000/250

● -2400 < -x < -2000

Multiply both sides by -1 and switch the signs

● 2000 < x < 2400

The correct option is D. 2000<= x <= 2400

Given, the value of an airplane depends on the flight hours,

[tex]V= 1800000-250x[/tex], here x is the flight hours.

We have to calculate the range of x After one year.

Since, [tex]V= 1800000-250x[/tex]

[tex]250x=1800000-V\\\\x=\dfrac{1800000-V}{250}[/tex]

Since the value of the plane is between $1,200,000 and $1,300,000. So,

[tex]x=\dfrac{1800000-1200000}{250}[/tex]

[tex]x=\dfrac{600000}{250}[/tex]

[tex]x=2400\\[/tex]

When V is 1300000 then x will be,

[tex]x=\dfrac{1800000-1300000}{250} \\[/tex]

[tex]x=\dfrac{500000}{250}[/tex]

[tex]x=2000[/tex]

Hence the range of x will be from 2000 to 2400.

The correct option is D. 2000<= x <= 2400.

For more details on range follow the link:

https://brainly.com/question/10185991

Answer:

A natural number is a number that occurs commonly and obviously in nature. As such, it is a whole, non-negative number.

Step-by-step explanation:

Answer:

Finite

Step-by-step explanation:

please give me brainliest

Answer:

She must consider 3507 components to be 90% sure of knowing the mean will be within ± 0.1 mm.

Step-by-step explanation:

We are given that an engineer wishes to determine the width of a particular electronic component. If she knows that the standard deviation is 3.6 mm.

And she considers to be 90% sure of knowing the mean will be within ±0.1 mm.

As we know that the margin of error is given by the following formula;

The margin of error =  [tex]Z_(_\frac{\alpha}{2}_) \times \frac{\sigma}{\sqrt{n} }[/tex]  

Here, [tex]\sigma[/tex] = standard deviation = 3.6 mm

         n = sample size of components

         [tex]\alpha[/tex] = level of significance = 1 - 0.90 = 0.10 or 10%

         [tex]\frac{\alpha}{2} = \frac{0.10}{2}[/tex] = 0.05 or 5%

Now, the critical value of z at a 5% level of significance in the z table is given to us as 1.645.

So, the margin of error =  [tex]Z_(_\frac{\alpha}{2}_) \times \frac{\sigma}{\sqrt{n} }[/tex]  

                  0.1 mm        =  [tex]1.645 \times \frac{3.6}{\sqrt{n} }[/tex]

                    [tex]\sqrt{n} = \frac{3.6\times 1.645}{0.1 }[/tex]

                    [tex]\sqrt{n}[/tex] = 59.22

                     n = [tex]59.22^{2}[/tex] = 3507.0084 ≈ 3507.

Hence, she must consider 3507 components to be 90% sure of knowing the mean will be within ± 0.1 mm.

Answer:

9

Step-by-step explanation:

First, find x. Since x is the average of the three number, add the three up and then divided by three. Thus:

[tex]x=\frac{13+-16+6}{3}=3/3=1[/tex]

y is the cube root of 8. Thus:

[tex]y=\sqrt[3]{8}=2[/tex]

So:

[tex]x^2+y^3\\=(1)^2+(2)^3\\=1+8=9[/tex]

Answer:

ljih

Step-by-step explanation:

Answer:

x > -6

Step-by-step explanation:

-5x — 10 < 20

Add 10 to each side

-5x — 10+10 < 20+10

-5x < 30

Divide each side by -5, remembering to flip the inequality

-5x/-5 > 30/-5

x > -6

Answer:

Step-by-step explanation:

[tex]-5x - 10 < 20\\\\\mathrm{Add\:}10\mathrm{\:to\:both\:sides}\\\\-5x-10+10<20+10\\\\\mathrm{Multiply\:both\:sides\:by\:-1\:\left(reverse\:the\:inequality\right)}\\\\\left(-5x\right)\left(-1\right)>30\left(-1\right)\\\\\mathrm{Simplify}\\\\5x>-30\\\\\mathrm{Divide\:both\:sides\:by\:}5\\\\\frac{5x}{5}>\frac{-30}{5}\\\\x>-6[/tex]

Answer:

-2 is the y-intercept of this function.

Step-by-step explanation:

Answer:

Step-by-step explanation:

If  the path of the longest shot put by the Women’s track team at Sun Devil U is modeled by h(x) = -0.015x² + 1.08x + 5.8 where x represents the horizontal distance from the start and h(x) is the height of the shot put above the ground, to determine h(24), we will have to substitute x = 24 into the modeled equation as shown;

[tex]h(x) = -0.015x^2 + 1.08x + 5.8\\\\if \ x = 24;\\\\h(24) = -0.015(24)^2 + 1.08(24) + 5.8\\\\h(24) = -0.015(576)+25.92+5.8\\\\h(24) = -8.64+31.72\\\\h(24) = 23.08\\[/tex]

Hence the value of the height at the horizontal distance of 24 feet is 23.08 feet to 2 decimal place.