x²-2x-8=0(x-4)(x+2)=0x=4,x=-2(x-1)+(x+3)(x-3)+(x-3)(x-1)=x-1+x²-9+x²-4x+3=2x²-3x-7当x=4时,原式=2×4²-3×4-7=13当x=-2时,原式=2×(-2)²-3×(-2)-7=7