x^2-y^2+2x+1
问题描述:
x^2-y^2+2x+1
答
x^2-y^2+2x+1
=(x+1)²-y²
=(x+y+1)(x-y+1)
x^2-y^2+2x+1
x^2-y^2+2x+1
=(x+1)²-y²
=(x+y+1)(x-y+1)