Question

Solve the system algebraically.

2x+ y - 10 = 0
x - y - 4 = 0

What is the value of y?

Answer 1

Okay, because this is a system, it's not just two equations. y will be the same for both equations.

2x + y - 10 = 0
x - y - 4 = 0

You want to solve for y, so you have to multiply the bottom equation by -2 so that you can eliminate x when you add them together.
2x + y - 10 = -2x + 2y + 8
y - 10 = 2y + 8
-y - 10 = 8
-y = 18
y = -18

Answer 2

Thanks ikram.