Question

In order to solve the following system of equations by subtraction, which of

the following could you do before subtracting the equations so that one
variable will be eliminated when you subtract them?
4x – 2y=7
3.x – 3y = 15
A. Multiply the top equation by 15 and the bottom equation by 7.
B. Multiply the top equation by 1/3.
O C. Multiply the top equation by 3 and the bottom equation by 4.
D. Multiply the top equation by-3 and the bottom equation by 2.

Answer 1

4x – 2y=7

3x – 3y = 15

we want to keep y by eliminating the x

so we will Multiply the top equation by 3 and the bottom equation by 4.

we will get

12x - 6y = 21

12x - 12y = 60

we subtract the equations

12x - 6y - 12x - (-12y) = 21 - 60

6y = -39 and so on