+130560 sqrt ( x + 36) + 6 = x subtract 6 from both sides
sqrt (x + 36) = x - 6 square both sides
x + 36 = x^2 - 12x + 36 subtract 36 from both sides
x = x^2 - 12x rearrange as
x^2 + 13x = 0 factor
x ( x + 13) = 0 set both factors to 0 and x = 0 [reject this] or x = 13 [accept this]
