How do you solve this equation?

the square root of x-3 minus 3 times the square root of x+12 equals -11.

(x-3)^(1/2) - 3(x+12)^1/2 = -11

x-3 = [-11 + 3(x+12)^1/2]^2
x-3 = 121 -66 + 9(x+12)^2 + 9(x+12)
x = 58 + 9(x+12)^2 + 9(x+12)
That can be reduced to a quadratic and solved for x