m²(m+1)-(m+1)
=(m+1)[m²-(m+1)]
=(m+1)(m²-m-1)
(x-2)²-2x+5
=x²-4x+4-2x+5
=x²-6x+9
=(x-3)²
(x-y)³-4(x-y)²-4(y-x)
=(x-y)³-4(x-y)²+4(x-y)
=(x-y)[(x-y)²-4(x-y)+4]
=(x-y)(x-y-2)²
不懂追问~