4(3x+7)=136 multiply out the 4 or distribute it
12x + 28 = 136 next subtract 28 from each side
12x = 108 now divide each side by 12
x = 9
OR
4(3x+7)=136 divide each side by 4
3x + 7 = 34 now subtract 7 from each side
3x = 27 divide each side by 3
x = 9
check: 4(3(9)+7) = 136 136=136