Question

Solve by the substitution method: x=y-4
2x+2y=12

Answer 1

2(y-4)+2y=12
2y-8+2y=12
4y-8=12
4y=20
y=5

to find x just plug y in to one of the other equations
x=5-4
x=1

2(1)+2(5)=12?
2+10=12?
12=12!