(x+2y-3)(x+2y+1)-5 十字相乘 因式分解

问题描述:

(x+2y-3)(x+2y+1)-5 十字相乘 因式分解

(x+2y-3)(x+2y+1)-5
=[(x+2y)-3][(x+2y)+1]-5
=(X+2y)2平方-2(X+2y)-3-5
=(X+2y)2平方-2(X+2y)-8
=(x+2y+2)(x+2y-4)

(x+2y-3)(x+2y+1)-5
=(x+2y)²-2(x+2y)-3-5
=(x+2y)²-2(x+2y)-8
=(x+2y+2)(x+2y-4)