①-3xy-92-1/4x2 ②﹙4x²+5x﹚²-﹙5x+16﹚²③﹙x+y﹚﹙x-1﹚-xy-xy² ④x³﹙x-y﹚+4x﹙y-x﹚

问题描述:

①-3xy-92-1/4x2 ②﹙4x²+5x﹚²-﹙5x+16﹚²
③﹙x+y﹚﹙x-1﹚-xy-xy² ④x³﹙x-y﹚+4x﹙y-x﹚

①-3xy-92-1/4x2
=-3xy-92-1/2
=-3xy-185/2
②﹙4x²+5x﹚²-﹙5x+16﹚²
=[4x²+5x-5x-16][4x²+5x+5x+16]
=(9x²-16)(4x²+10x+16)
=2(3x-4)(3x+4)(2x²+5x+8)