x = 5
since we know y= 5 + x , plug this into y in the second equation.
2x + 2 (5 + x) = 30
distribute 2 into the 5 and x
2x + 10 + 2x = 30
combine like terms
4x + 10 = 30
subtract 10 from both sides
4x = 20
divide four by both sides to isolate the variable
x = 5
