Question

Which of these strategies would eliminate a variable in the system of equations?

-x+6y=8
7x -y = -2

Choose all answers that apply:

(Choice A)
A Multiply the bottom equation by 6, then subtract the bottom equation from the top equation.

(Choice B)
B Add the equations.

(Choice C)
C Multiply the top equation by 7, then add the equations.

Answer 1

B) Subtract the bottom equation from the top equation

C) Add the equations.

Step-by-step explanation:

We have to eliminate a variable in the system of equations

6x + 5y = 1 . (1) and

6x - 5y = 7 (2) and,

Since the y-term on both the equations are the same but opposite in sign, therefore the strategy to eliminate y variable from the system of equations (1) and (2) is to add the equations. (Answer)

Again, the x-terms are the same and with a similar sign, therefore, by subtracting the bottom equation from the top equation we can also eliminate the x-variable. (Answer)

Explanation:

Answer 2

Multiply the top equation by 7, then add the equations.

Explanation:

I just did it Khan Academy.