2 [ ( 12 + 2x) + ( 15 + 2x) ] = 74
Divide 2 by both sides.
[ ( 12 + 2x) + ( 15 + 2x) ] = 37
Add the equations in the parentheses.
(27 + 4x) = 37
Remove parentheses.
27 + 4x = 37
Subtract 27 by both sides.
4x = 10
Divide 4 by both sides.
x = 10/4 or 2.5
