(a-1/2)[(a+1/2b)²-(a-1/2b)²]﹙a²+1/2ab+b²﹚-2b﹙a⁴-1﹚
=(a-1/2)*2ab﹙a²+1/2ab+b²﹚-2b﹙a⁴-1﹚
请检查题目打错了。是(a-1/2b)[(a+1/2b)²-(a-1/2b)²]﹙a²+1/2ab+b²﹚-2b﹙a⁴-1﹚写出详细过程(a-1/2b)[(a+1/2b)²-(a-1/2b)²]﹙a²+1/2ab+b²﹚-2b﹙a⁴-1﹚=2ab[a^3-(1/4)ab^+ab^-(1/2)b^3]-2b(a^4-1)=(3/2)a^b^3-ab^4+2b,a=2，b=-1时原式=-6-2-2=-10.