计算(X+2Y-1)(X+2Y+1)
问题描述:
计算(X+2Y-1)(X+2Y+1)
答
(X+2Y-1)(X+2Y+1)
=(x+2y)²-1
=x²+4xy+4y²-1
答
原式=[(X+2Y)-1][(X+2Y)+1]
=(X+2Y)²-1²
=X²+4XY+4Y²-1