4b²c²-(c²+b²)²急求

问题描述:

4b²c²-(c²+b²)²急求

4b²c²-(c²+b²)²
=(2bc)²-(c²+b²)² 运用平方差公式
=[2bc+(c²+b²)] [2bc-(c²+b²)]
=(b²+2bc+c²)[-(b²-2ab+c²) ]
=(b+c)²×[-(b-c)²]
= -(b+c)²(b-c)²