Question

Solve the system of equations using elimination. 4x - 7y = 5 9x – 7y = –15

Answer 1

Step-by-step explanation:

We have to get one positive 7y so,

4x-7y=5

9x-7y=-15

multiply anyone of the equation by -1. I choose the first one so,

4x+7y=-5

9x-7y=-15

we can now cancel the y's so the equation will be left with

-4x=-5

9x=-15

add the equations

5x=-20

divide by 5 n u get

x=-4

now plug in the x value in any one of the

equations

I choose the first one so,

4(-4)-7y=5

-16-7y=5

add 16 to both sides

-7y=21

divide by -7

y=-3.

finally check.