应用(a+b)(a-b)=a2-b2的公式计算(x+2y-1)(x-2y+1),则下列变形正确的是( ) A.[x-(2y+1)]2 B.[x+(2y+1)]2 C.[x-(2y-1)][x+(2y-1)] D.[(x-2y)+1][(x
问题描述:
应用(a+b)(a-b)=a2-b2的公式计算(x+2y-1)(x-2y+1),则下列变形正确的是( )
A. [x-(2y+1)]2
B. [x+(2y+1)]2
C. [x-(2y-1)][x+(2y-1)]
D. [(x-2y)+1][(x-2y)-1]
答
(x+2y-1)(x-2y+1)=[x-(2y-1)][x+(2y-1)].
故选C.