Solve.

x=√6x-27 +3

Assuming the usual sloppiness with parentheses, I'll assume

x=√(6x-27)+3
x-3 = √(6x-27)
x^2-6x+9 = 6x-27
x^2-12x+36 = 0
(x-6)^2 = 0
x = 6