How to solve y=-x+4; y=2x-8 using substitution?

In this problem why is the easiest to substitute.

Just set the equations equal to each other because they both equal y

-x + 4 = 2x - 8

(You want to get all the x's to one side so add x to each side)

4 = 3x - 8

(next add 8 to both sides)

12 = 3x

(lastly divide 3 from both sides)

4 = x

You have got your x so now it is time to find that y just replace x to either of the two equations

y = 2 (4) - 8 or y = - (4) + 4

y = 8 - 8 y = 0

y = 0

Final Answer: y=0, x=4