﹙x+y﹚﹙x-y+1﹚是如何出来的??????
追答提取公因式(x+y)
(x+y)(x-y)+(x+y)=)=(x+y)(x-y)+(x+y)*1
﹙x+y﹚﹙x-y+1﹚是如何出来的??????
追答提取公因式x+y
﹙x+y﹚﹙x-y+1﹚是如何出来的??????
追答x^2-y^2=(x+y)(x-y)知道这个式子就行了
﹙x+y﹚﹙x-y+1﹚是如何出来的??????
追答从(x+y)(x-y)+(x+y)里提取公因式(x+y),左边有(x-y)个(x+y),右边有1个(x+y),所以左右两边都提取公因式(x+y),就得出﹙x+y﹚﹙x-y+1﹚.