计算 3(2a+1)(2a-1)-4(3a-2)(3a+5)=
问题描述:
计算 3(2a+1)(2a-1)-4(3a-2)(3a+5)=
答
3(2a+1)(2a-1)-4(3a-2)(3a+5)
=3(4a²-1)-4(9a²+9a-15)
=12a²-3-36a²-36a+60
=-24a²-36a+57