﹙③﹙x+y﹚﹙x-1﹚-xy-xy² ④x³﹙x-y﹚+4x﹙y-x﹚

问题描述:

﹙③﹙x+y﹚﹙x-1﹚-xy-xy² ④x³﹙x-y﹚+4x﹙y-x﹚

③﹙x+y﹚﹙x-1﹚-xy-xy²
=x²-x-y+xy-xy-xy²
=x²-x-y-xy²
④x³﹙x-y﹚+4x﹙y-x﹚
=(x³-4x)﹙x-y﹚
=x(x-2)(x+2)﹙x-y﹚