Question

Solve the following system of equations: y=x+4 2x+y=13

Answer 1

Substitute y from the first equation into the second:

2x+(x+4)=13
3x+4=13
3x=9
x=3.

Answer 2

Okay, for this one is will use substitution:
y=x+4
y-x=4
2y-2x=8

-2x+2y=8
+
2x+y=13
=
3y=21
y=7
x=3 is your final answer. Hope it help!