解一元二次方程.（1）x²+6x=1 （2）x²-14x=18 （3） x²+2x+2=8x+4

(1) x^2+6x=1 => (x+3)^2=1+9=10 => x+3=±√10 => x=-3±√10(2) x^2-14x=8 => (x-7)^2=8+49=57 => x-7=±√57 => x=7±√57(3) x^2+2x+2=8x+4 => x^2-6x=2 => (x-3)^2=2+9=11 => x-3=±√11 => x=3±√11