1-3(X-Y)＋3(X-Y)²-(X-Y)3次方次方因式分解

1-3(X-Y)＋3(X-Y)²-(X-Y)3次方次方因式分解
1-3(X-Y)＋3(X-Y)²-(X-Y)3次方次方因式分解

1-3(X-Y)＋3(X-Y)²-(X-Y)3次方次方因式分解
令a=x-y
原式=-(a³-1)+3a²-3a
=-(a-1)(a²+a+1)+3a(a-1)
=-(a-1)(a²+a+1-3a)
=-(a-1)(a²-2a+1)
=-(a-1)³
=-(x-y-1)³

设a=x-y
原式=1-3a+3a²-a³
=-(a-1)³
=-(x-y-1)³