Question

Which of the following options could you do before subtracting the equations so that one variable will be eliminated when you subtract them?

Answer 1

We need to do something to both equations so we can eliminate one variable

We can multiply the first equation by 3 and the second equation by 4

3( 4x-2y = 7) yields 12x -6y = 21

4( 3x-3y = 15) yields 12x -12y = 60

Now when we subtract

12x -6y = 21

-(12x -12y = 60)

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12x -6y = 21

-12x +12y = -60

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6y = 39

The x terms are eliminated

Choice D multiply the top equation by 3 and the bottom equation by 4