(x-6)(x+6)-(2x-3)=6-x²

(x-6)(x+6)-(2x-3)=6-x²
x²-6²-2x+3=6-x²
x²-36-2x+3=6-x²
2x²-2x-39=0
D=2²+4*2*39=4+312=316
√D=√316=2√79
x=(2±2√79)/4=(1±√79)/2