∵x²-2x=2∴x²-2x+1=3即（x-1）²=3原式=（x-1)²+(x+3)(x-3)+(x-3)(x-1) =（x-1）²+(x-3)(x+3+x-1) =(x-1)²+2(x-3)(x+1) =(x-1)²+2(x²-2x-3) =3+2×（-1） ...