Question

What is a possible first step to eliminate a variable in the following system?
7x – 9y = 2
3x – 6y = –4

A. Multiply the first equation by 2 and the second equation by –3.

B. Multiply the first equation by –3 and the second equation by –2.

C. Multiply the first equation by 7 and the second equation by 3.

D. Multiply the first equation by –2 and the second equation by 4.

Answer 1

7x-9y=2

3x-6y=-4

When doing elimination the idea is to get one of the variables to cancel out.

2(7x-9y)=2(2) = 14x-18y=4 [first equation]

-3(3x-6y)=-3(-4) = -9x+18y=-12 [second equation]

You'll notice that the y's in this case cancel each other out.

Multiply the first equation by 2 and the second equation by -3

Answer 2

ThankYou!! :)