分解因试（x-1)²-2(x-1)+1 x³y-2x²y²+xy³

分解因试（x-1)²-2(x-1)+1 x³y-2x²y²+xy³
分解因试（x-1)²-2(x-1)+1 x³y-2x²y²+xy³

分解因试（x-1)²-2(x-1)+1 x³y-2x²y²+xy³
（x-1)²-2(x-1)+1
=[(x-1)-1]²
=(x-2)²
x³y-2x²y²+xy³
=xy(x²-2xy+y²)
=xy(x-y)²