5(5 + x) = 11(9 + x)
25 + 5x = 99 + 11x
Subtract 5x from both sides and 99 from both sides to get variables on one side and constants on the other.
25 - 99 = 11x - 5x
-74 = 6x
Divide by 6 on both sides to isolate the variable.
-74/6 = x or -12 and 1/3 = x