how to solve this

Question

y=x-8

y=2x-12

solve by substitution

Answer 1

From eq #1, x = y + 8

Plug into eq #2, giving y = 2(y + 8) - 12, and therefore y = 2y + 4, so y = -4.

Plug back into eq #1, x = -4 + 8 = 4

You can also verify by plugging the values of x and y into the original equations.