3(1/3a-b)² (-a-2b)²
问题描述:
3(1/3a-b)² (-a-2b)²
答
3(1/3a-b)² (-a-2b)²
=3(a²/9-2ab/3+b²)
=a²/3-2ab+3b²
(-a-2b)²
=(a+2b)²
=a²+4ab+4b²