(1)(x+y)²-4(x+y)+4
原式=(x+y)²-4(x+y)+2²
=(x+y-2)²
(2)2a(b-c)²-3b+3c
原式=2a(b-c)²-3(b-c)
=(b-c)(2ab-2ac-3)
(3)x³-2x²y+xy²-x
原式=x(x²-1) -xy(2x-y)
=x[x²-1-y(2x-y) ]
=x(x²-2xy+y²-1)
(1)(x+y)²-4(x+y)+4
原式=(x+y)²-4(x+y)+2²
=(x+y-2)²
(2)2a(b-c)²-3b+3c
原式=2a(b-c)²-3(b-c)
=(b-c)(2ab-2ac-3)
(3)x³-2x²y+xy²-x
原式=x(x²-1) -xy(2x-y)
=x[x²-1-y(2x-y) ]
=x(x²-2xy+y²-1)