3a²b-[2a²b-(2ab-a²b)-4a²]-3ab
=3a²b-[2a²b-2ab+a²b-4a²]-3ab
=3a²b-[3a²b-2ab-4a²]-3ab
=2ab+4a²-3ab
=-ab+4a²
=-（-2*-3）+4*（-2）²
=-6+16
=10�Ȼ�������ֵ��4x��3�η�-[-x��ƽ��+2(x������-3��֮1x��ƽ��)]������x=-34x³-[-x²+2��x³-1/3x²��]=4x³-[-x²+2x³-2/3x²��]=4x³-[-5/3x²+2x³]=2x³+5/3x²=x²��2x+5/3��=��-3��²��-6+5/3��=-54+9*5/3=-54+15=-39