The work of a student to solve a set of equations is shown:
Equation A: y = 10 - 22
Equation B: 5y = 2 - 4z
Step 1: -5(y) = -5(10 – 2z) [Equation A is multiplied by -5.]
5y = 2 - 42 [Equation B]
Step 2: _5y = 10-22 [Equation A in Step 1 is simplified.]
5y = 2 - 4z [Equation B]
Step 3:
0 = 12 - 6 [Equations in Step 2 are added.]
Step 4:
z = 12
Step 5:
z = 12
In which step did the student first make an error?

Answers

Answer 1

Answer:

Step 2.

Step-by-step explanation:

Given the two equations,

Equation A: y = 10 - 2z

Equation B: 5y = 2 - 4z solved by a student, we are to determine the step where the student made an error in his/her calculation. Let's follow the steps;

Step 1: multiply equation A by -5. The essence of this is to be able to cancel out one of the variables and calculate for the other variable. On multiplication we have;

y = 10 - 2z × (-5)

5y = 2 - 4z × (1)

_____________________

-5y = -5(10-2z) .... A

5y = 2 - 4z..... B

Step 2: simplify equation A by opening the bracket.

-5y = -5(10)+5(2z)

-5y = -50+10z

The equations become;

-5y = -50+10z .... A

5y = 2 - 4z..... B

It can be seen that her simplified expression does not tally with what we got i.e -5y = -50+10z. This was the step the student made the first error.

Since this student step is wrong, the remaining calculation will be wrong.

Let us fix the calculation steps now.

We will continue from the previous step.

Step3: Add equation A and B in step 2 together.

-5y+5y = (-50+2)+(10z-4z)

0 = -48+6z

Step 4: Add 48 to both sides:

0+48 = -48+6z+48

48 = 0+6z

48 = 6z

Step 5: Divide both sides by 6

48/6 = 6z/6

6 = z

z= 6

Hence, the value of z = 6 not 12 and the student made his/her first error in step 2.


Related Questions

A spinner contains 3 equal sections: one red, one yellow, and one blue. The possible results of two spins are shown in the tree diagram below. What is P(red, then yellow)?

Answers

1/9

3 x 3 = 9 (since it is spun twice)

1/9

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

Answer:

1/9

Step-by-step explanation:

Probability of spinning a red =  1/3

Probability of spinning a yellow = 1/3

So Probability of getting red and then yellow = 1/3 x 1/3 = 1/9

Shawn wanted to model the number 13,450 using 13,450 using base-ten blocks how many large cubes, flats, and longs does he need to model the number

Answers

Answer:

See attached

Step-by-step explanation:

13450 = 13000 + 400 + 50

13*1000  = 13 large cubes4*100      = 4 flats5*10        = 5 longs

Find the missing probability. P(A)=720,P(B)=35,P(A∩B)=21100 ,P(A∪B)=?

Answers

P (A U B) = 37/50

7/20+3/5+21/100

The missing probability P(A∪B) will be 37/50.

What is the probability?

Probability refers to a possibility that deals with the occurrence of random events.

The probability of all the events occurring need to be 1.

Given information;

P(A)= 7/20,

P(B)=3/5,

P(A∩B) =21/100 ,

We need to find the missing probability P(A∪B).

We know that

P(A∪B)= P(A) + P(B) + P(A∩B)

P(A∪B) = 7/20 + 3/5 + 21/100

P (A U B) = 37/50

Therefore, the missing probability P(A∪B) will be 37/50.

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which expression is equivalent to (3x-6)(4x+1)

Answers

Answer:

12x^2 -21x -6

Step-by-step explanation:

(3x-6)(4x+1)

FOIL

first 3x*4x= 12x^2

outer 3x*1 = 3x

inner -6*4x = -24x

last  -6*1 = -6

Add them together

12x^2 +3x -24x -6

Combine like terms

12x^2 -21x -6

A number if that number and the number b sum to 40.

Answers

Answer:

40-b

Step-by-step explanation:

x is the unknown number

x+b = 40

We want to find x

Subtract b from each side

x+b-b = 40 -b

x = 40-b

The unknown number is 40-b

Answer:

[tex]\huge \boxed{40-b}[/tex]

Step-by-step explanation:

[tex]\sf Let \ x \ be \ that \ number.[/tex]

[tex]x+b=40[/tex]

[tex]\sf Solve \ for \ x.[/tex]

[tex]\sf Subtract \ b \ from \ both \ sides.[/tex]

[tex]x+b-b=40-b[/tex]

[tex]\sf Simplify \ the \ equation.[/tex]

[tex]x=40-b[/tex]

65. Given a segment with endpoints A and C and midpoint. If A(5, 8), and M(-3,2). Find the
location of C.

Answers

Answer:

C(-11,-4)

Step-by-step explanation:

Please answer this question now

Answers

Answer:

82 degrees

Step-by-step explanation:

Measure of arc ABC = 86*2 = 172 degrees.

Measure of arc DC = 360 - (145+172) = 360-317 = 43 degrees.

Measure of arc BCD = 121+43 = 164 degrees.

Measure of angle A = 164/2 = 82 degrees

the answer is 82 degrees

Which of the following points lie in the solution set to the following system of inequalities? y < −3x + 3 y < x + 2 (1, −5) (1, 5) (5, 1) (−1, 5)

Answers

Answer: (1, −5)

Step-by-step explanation:

Plot the given inequalities on coordinate plane.

For y < −3x + 3, plot y =−3x + 3

At x=0,  y= 3

At y =0, 0=-3x+3

⇒ x= 1

so, plot points (0,3) and (1,0) and join to get y =−3x + 3, since inequality has '<' sign, so shade( in red) below line area and line should be dotted.

For  y < x + 2, plot  y = x + 2

At x=0,  y= 2

At y =0, x=-2

so, plot points (0,2) and (-2,0) and join to get y = x + 2, since inequality has '<' sign, so shade( in orange) below line area and line should be dotted.

Now, plot all given points (1, −5) (1, 5) (5, 1) (−1, 5), we can clearly observe that (1, −5) lies in the solution set.  (in common shaded region)

Answer:

The correct answer is 1, -5

Step-by-step explanation:

Lines T U and R S intersect lines M N and P Q. Where line T U intersects with lines M N and P Q, right angles are formed. Lines M N and P Q are straight lines that are next to each other and they will never intersect. Lines T U and R S are next to each other and could intersect. Which two statements are both true?

Answers

c. Tu | MN and MN || PQ I am done with the interview

Tim has an after-school delivery service that he

provides for several small retailers in town. He

uses his bicycle and charges $1.25 for a delivery

made within 1 mi, $1.70 for a delivery of at

least 1 mi but less than 1 mi, $2.15 for a

delivery of at least 1. mi but less than 2 miles,

and so on. If Tim raised his rates by 10%, what

would he be paid to deliver a package 35

miles?

Answers

Answer:

Step-by-step explanation:

tim has an after school delivery service that he provides for several small retailers in town. he uses his bicycle and charges $1.25 for a delivery made within 1 1/2 miles, $1.70 for a delivery of at least 1 1/2 miles but less than 1 3/4 miles. $2.15 for a delivery of at least 1 3/4 miles but less than 2 miles, and so on. if tim raised his rates by 10%, what would he be paid to deliver a package 3 1/8 miles.

Answer:

From the question asked the cost of additional 1/4 mile (1 3/4 - 1 1/2) is $0.45 ($1.7 - $1.25). If the rate is increased by 10% (0.1), the new price for an additional 1/4 mile would be 1.1 (1 + 0.1) × 0.45 = $0.495.

Tim new charge rate are as follows:

$1.25 for a delivery made within 1 1/2 miles

$1.745 for a delivery of at least 1 1/2 miles but less than 1 3/4

$2.24 or a delivery of at least 1 3/4 miles but less than 2

$2.735 or a delivery of at least 2 miles but less than 2 1/4

$3.23 or a delivery of at least 2 1/4 miles but less than 2 1/2

$3.725 or a delivery of at least 2 1/2 miles but less than 2 3/4

$4.22 or a delivery of at least 2 3/4 miles but less than 3

$4.715 or a delivery of at least 3 miles but less than 3 1/4

Since 3 1/8 is within 3 miles and 3 1/4 miles, Tim would charge $4.715 to deliver a package 3 1/8 miles.

 

There is a regular dodecahedron with all the points connected to each other. What is the area if each of the shales formed if the distance between each Point is x?

Answers

Answer:

18581.16

Step-by-step explanation:

The area of each of the shale can be calculated as

distance between each point = x

The area of the regular Dodecahedron

A = [tex]\sqrt[3]{25+10\sqrt{5} } a^{2}[/tex]

where a = number of edges = 30

hence the area of the regular dodecaheron = 18581.16

Please answer quickly!

Answers

Answer:

T'(-1, -3)

U'(-8, -3)

V'(-9, -10)

W(1, -10)

Step-by-step explanation:

For each point, draw a segment from it to the line y = -x and perpendicular to the line, and extend it the same distance to the other side of the line.

T'(-1, -3)

U'(-8, -3)

V'(-9, -10)

W(1, -10)

1. Calculate the amount of gallons needed to fill the pool shown below.

Answers

Answer:

25,070 gal

Step-by-step explanation:

will make it simple and short.

vol =  ( a + b ) * h/2 times the depth

vol = (8 + 3.5) x (35/2) x 20 = 4025 cu. ft.  ---------->>> then convert to gal.

                              6.2288 gal

vol = 4025 cu.ft. x ----------------- =  25,070 gal

                                 1 cu.ft.

look at picture and solve​

Answers

Answer:

79°

Step-by-step explanation:

PQO is straight angle with measure of 180°

the given angles' sum makes 101° and we need 79 to complete it to 180° therefore the angle STQ = 79°

Please help solve this, I solved it on my own but I think my calculations are wrong. here is the problem,
b-(b+a×4c÷4); use; a=-6, b=1, and c=2?​

Answers

Hi there! Hopefully this helps!

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

Answer: 12~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

First we need to substitute the value of the variable into the expression and simplify.

b-(b+a×4c÷4) = 1 - (1 + -6 × 4(2) ÷ 4).

Now we need to solve 1 - (1 + -6 × 4(2) ÷ 4).

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1 - (1 + -6 × 4(2) ÷ 4)

|

|  First, we cancel out 4 and 4.

\/

1 - (1 - 6 × 2)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Next, we multiply -6 and 2 to get -12.

1 - (1 - 12)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Then we subtract 12 from 1 to get -11.

1 - (-11)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The opposite of -11 is 11.

1 + 11.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Add 1 and 11 to get, you guessed it, 12!

Answer:

Answer: 12

Hope this helps

. An image rotated around its centre point appears unchanged after 180° and 360° turns.
This is an example of:
a) line symmetry
b) rotation symmetry
c) tessellation
d) vertex​

Answers

It's an example of rotation symmetry, if the image appears unchanged. If the rotation symmetry exists there is a one centre point around which an image appears unchanged.

Answer:

It's an example of rotation symmetry, if the image appears unchanged. If the rotation symmetry exists there is a one centre point around which an image appears unchanged.

Find the midpoints of the points (-3,-2) and (1,-4)

Answers

Answer: (-1,-3)

Step-by-step explanation:

midpoint formula [tex]\left(\frac{x_2+x_1}{2},\:\:\frac{y_2+y_1}{2}\right)[/tex]

[tex]\left(x_1,\:y_1\right)=\left(-3,\:-2\right),\:\left(x_2,\:y_2\right)=\left(1,\:-4\right)[/tex]

[tex]\left(\frac{1-3}{2},\:\frac{-4-2}{2}\right)[/tex]

[tex](\frac{-2}{2},\frac{-6}{2})[/tex]

-2/2=-1

-6/2=-3

So the midpoint is (-1,-3)

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Find the area of the triangle. Give the answer to the nearest tenth. The drawing may not be to scale.

21.0 m^2
9.8 m^2
19.6 m^2
10.5 m^2

Answers

Answer:

10.5 m²

Step-by-step explanation:

Given:

∆ with 2 side lengths, 4.7m, 6.1m, and an included angle, 47°.

Required:

Area of the triangle

SOLUTION:

Area of such triangle that has 2 known sides and an included angle between them is given as ½*a*b*sin(θ).

Where,

a = 4.7 m

b = 6.1 m

θ = 47°

Area = ½*4.7*6.1*sin(47)

Area = 10.5 m² (to the nearest tenth)

Anyone help me.... BTW I need proper working. ​

Answers

Answer:

that answer i already give in another page...

You and your best friend are both on the swim team. You want to beat your friend at the next swim meet so you decide to swim 151515 minutes longer than she does one day at practice. Write an equation for the number of minutes you swim, yyy, when your friend swims xxx number of minutes.

Answers

Answer:

y = x + 15

Step-by-step explanation:

My friend swims x minutes.

I swim 15 minutes more than my friends, so I swim x + 15 minutes.

I swim y minutes, so y equals x + 15

Answer: y = x + 15

Write two different polynomials with a difference of
- 3x² + 5x - 7​

Answers

Answer:

(-5 +/- i√59)/-6

Step-by-step explanation:

(-5 +/- √25-84)/2(-3)

(-5 +/- i√59)/-6

Please answer this question now

Answers

Answer:

200 cubic centimeters is the answer :)

Step-by-step explanation:

Which system of equations represents the matrix shown below?

Answers

Answer:

D

Step-by-step explanation:

just compare the augmented matrix to the possible answers and you will see it the option D

Calculate the product below and give your answer in scientific notation. \large{\left(5.2\times 10^{-2} \right) \times \left(8.0\times 10^{-4} \right) =\ ?}(5.2×10 −2 )×(8.0×10 −4 )= ?Left parenthesis, 5, point, 2, times, 10, start superscript, minus, 2, end superscript, right parenthesis, times, left parenthesis, 8, point, 0, times, 10, start superscript, minus, 4, end superscript, right parenthesis, equals, space, question mark

Answers

The product of the numbers in scientific notation is 4.16 × 10⁻⁵

Given data:

To calculate the product, we multiply the coefficients and add the exponents of 10:

(5.2 × 10⁻²) × (8.0 × 10⁻⁴) = 5.2 × 8.0 × 10⁻² × 10⁻⁴

Multiplying the coefficients:

5.2 × 8.0 = 41.6

Adding the exponents of 10:

10⁻²× 10⁻⁴ = 10^(-2 - 4) = 10⁻⁶

Putting it all together:

(5.2 × 10⁻²) × (8.0 × 10⁻⁴) = 41.6 × 10⁻⁶

Hence, the final answer in scientific notation is: 4.16 × 10⁻⁵

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The cost of a pizza at the local pizza shop has a base price of $12 for a cheese pizza, plus $2 for each additional topping? What is the value of the slope?

Answers

Answer:

$2.

Step-by-step explanation:

This is because the base price is $12, which means the constant is 12. The toppings are the only things you can add to the pizza, so the price of each additional topping is the slope of the pizza's cost. The slope is 2 dollars.

Hope this helps!

Answer:

2

Step-by-step explanation:

If we were to write a linear equation in slope-intercept form (y = mx + b where m = slope and b = y-intercept) of this situation, it would be y = 2x + 12 where y is the price and x is the number of toppings. This is because the price for every topping is 2x but the base price doesn't change, therefore it's a constant so it would be + 12. In this case, since m = slope, the slope is 2.

1 minus tan square A by 2 by tan + square A by 2 equals to Cos A​

Answers

Answer:

trerjyhtrwgfdfeqrtgfnerwqdfgfgrqwefgn

Step-by-step explanation:

Which statement best illustrates using the vertical line test to determine if the graph below is a function of x? The graph is not a function of x because the line x = 0 intersects the graph at two points. The graph is a function of x because the line x = 5 does not intersect the graph. The graph is not a function of x because the line y = 0 intersects the graph at two points. The graph is a function of x because the line y = 5 does not intersect the graph.

Answers

Answer:

The graph is not a function of x because the line x = 0 intersects the graph at two points.

Step-by-step explanation:

This graph is not a function because it fails the vertical line test, since several vertical lines would intersect the graph at 2 points.

This answer choice is correct, as the line x = 0 intersects the graph at 2 points, (0, 2) and (0, -2).

Answer:

A

Step-by-step explanation:

how to write x divided by 16 in algebraic expression

Answers

Answer:

x/16 the line means your dividing the x by 16

Step-by-step explanation:

The sum of three consecutive numbers is greater than 40. The inequality that represents this is x+x+1+x+2>40. Which value of x hold true for the inequality?

Answers

Answer:

x can be any integer greater than 12.

Step-by-step explanation:

x + x + 1 + x + 2 > 40

3x + 3 > 40

3x > 37

x > 12 1/3

x can be any integer greater than 12.

Pens cost 15 pence each.
Rulers cost 20 pence each.

A school buys 150 pens and 90 rulers.
The total cost is reduced by 1/5


How much does the school pay?

Answers

Answer:

The amount the school pays is £32.40

Step-by-step explanation:

The cost of each pen = 15 pence

The cost of each ruler = 20 pence

The number of pens bought by the school = 150

The number of rulers bought by the school = 90

The cost reduction (discount) on the items bought = 1/5

Therefore, we have;

The total cost of the pens bought by the school = 150 × 15 = 2250 = £22.50

The total cost of the rulers bought by the school = 90 × 20 = 1800 = £18.00

The total cost of the writing materials (rulers and pens) bought by the school = £22.50 + £18.00 = £40.50

The discount = 1/5 total cost reduction = 1/5×£40.50  = $8.10

The amount the school pays = The total cost of the writing materials - The discount

The amount the school pays = £40.50 - $8.10 =  £32.40

The amount the school pays =  £32.40.

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