证明:81a4+4b4=(9a²+6ab+2b²)(9a²-6ab+2b²)

问题描述:

证明:81a4+4b4=(9a²+6ab+2b²)(9a²-6ab+2b²)

左边=81a^4+36a²b²+4b^4-36a²b²
=(9a²+2b²)²-(6ab)²
=(9a²+6ab+2b²)(9a²-6ab+2b²)=右边