23y2的知识精选

先化简,再求值:-2x2-2[3y2-2(x2-y2)+6],其中x=-1,y=-2.
问题详情:先化简,再求值:-2x2-2[3y2-2(x2-y2)+6],其中x=-1,y=-2.【回答】-2x2-2[3y2-2(x2-y2)+6]=-2x2-2[3y2-2x2 +2y2+6]·······················································...
 3(2x2-y2)-2(3y2-2x2)
问题详情: 3(2x2-y2)-2(3y2-2x2)【回答】解:原式=6x2-3y2-6y2+4x2=10x2-9y2.知识点:整式的加减题型:计算题...
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