Question

If you wanted to eliminate the y variable by adding the two equations in the following system, what could be your first step?

5x − 6y = 6
x − y = 12

Add the two equations together

Multiply the second equation by −6

Multiply the first equation by −6

Multiply the second equation by 6

Answer 1

You can arrive at the correct choice by seeing which choice gives the requires result (eliminate the y variable).
Would adding the two equations together eliminate the y variable when
-6y + (-y) = -7y ?

Answer 2

no

Answer 3

Correct. Looking at the second choice, if you multiply the second equation by -6 the y variable becomes -y * -6 = 6y
Would adding the two equations together eliminate the y variable when
-6y + 6y = 0 ?

Answer 4

yes

Answer 5

You have your answer then.

Answer 6

so a?