Answer: x = 3
y = -1
There are many ways to do the systems of equations. To solve this, I used the substitution method.
Isolate y or x (whichever is easier) in the first equation IF NECESSARY.
y = x - 4 --> it's already given
Substitute in (x - 4) for y in the second equation.
2x + (x - 4) = 5 Distributive Property
2x + x - 4 = 5 Combine like terms
3x - 4 = 5 Add 4 to both sides
3x = 9 Divide by 3 to both sides
x = 3 Answer!
Substitute in (3) for x in the first equation.
y = (3) - 4 Simplify
y = -1 Answer!