:1.x的5次方-x的3次方=x³(x²-1)=x³(x+1)(x-1)x的平方(y-8)+8的2次方(8-y)=x²(y-8)﹣8²(y-8)=(x²-8²)(y-8)=(x+8)(x-8)(y-8)(x-1)(x+2)的3次方-4(x-1)的3次方(x+2)=(x-1)(x+2){(x+2)²-[2(x-1)]²}=(x-1)(x+2)(x+2+2x-2)(x+2-2x+2)=3x(x-1)(x+2)(4-x)