Supply the missing parts of each of the solution of the following equations.

(x-3)²+(x+6)²=81
(x²____+9)+(x²____+36)=81
x²+x²-6x+12x+12x+9+36=81
2x²____+45=81
2x²+6x+45-81=____

x²____+-18=0
(x+6)(x-3)=0

x+6=0 or x-3=0
x=_____ x=_____​