Question

How do you solve x-2y=1 y=-x+4 by using substitution?

Answer 1

Well, you know what y is:, so put y in the second equation:

x - 2(-x+4) = 1
x + 2x - 8 = 1
3x -8 = 1
3x = 9
x = 3

Then, plug for x in the original equation to get:
y = -(3) + 4 = 1

Therefore, x = 3 and y = 1.

Answer 2

Thank you sir!