3(2X²Y-3XY²）-2（2XY²-3X²Y）=6X²Y-9XY²-4XY²+6X²Y=12X²Y-13XY²,其中X=1,Y=-1.17
=12*(-1.17)-13(-1.17)(-1.17)=31.8357
3A²-2（2A²+A）+2（A²-3A）=3A²-4A²-2A+2A²-6A=A²-8A=4+16=20