x²-y²+x+y

问题描述:

x²-y²+x+y

x²-y²+x+y
=(x+y)(x-y)+(x+y)
=(x+y)(x-y+1)

x²-y²+x+y
=(x²-y²)+(x+y)
=(x+y)(x-y)+(x+y)
=(x+y) (x-y+1)