Question

Petro was given this system of equations.

-14x-2y = 24

14x+8y = -12

Petro’s work is shown in the table. Where, if anywhere, did Petro first make a mistake?

-
A) step 1
B) step 2
C) step 3
D) no mistake

Answer 1

Step 3 in the correct answer. Thx. Just to verify with everyone it is step 3.

Explanation:

On Edge 2020 got it correct.

Answer 2

Option C step 3

Explanation:

we have

-14x-2y=24 ------> equation A

14x+8y=-12 -----> equation B

step 1

Solve the system by elimination

Adds equation A and equation B

-14x-2y=24

14x+8y=-12

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

-2y+8y=24-12

6y=12

The step 1 is correct

step 2

Solve for y

Divide by 6 both sides

6y/6=12/6

y=2

The step 2 is correct

step 3

Find the value of x

substitute the value of y in the equation A

-14x-2(2)=24

-14x-4=24

14x=-4-24

14x=-28

x=-2

The step 3 is not correct

therefore

Petro first make a mistake in Step 3