(2x-y+1)(2x+y+1)怎么做?
问题描述:
(2x-y+1)(2x+y+1)怎么做?
答
(2x+1+y)(2x+1-y)=(2x+1)^2-y^2=4x^2+4x+1-y^2
答
(2x+1+y)(2x+1-y)=4x^2+2x-2xy+2x+1-y+2xy+y-y^2=4x^2+4x-y^2+1
答
=(2x+1+y)(2x+1-y)
=(2x+1)²-y²
=4x²+4x+1-y²
答
令2x+1为Z
则原式化为 (Z-y)×(Z+y)=Z^2-y^2=(2x+1)^2-y^2=4x^2+4x+1-y^2