计算:(1),-3(2a-3)+7a+8;(2),(2xy-y)-(-y+xy)
2个回答
解
-3(2a-3)+7a+8
=-6a+9+7a+8
=(-6a+7a)+(9+8)
=a+17
(2xy-y)-(-y+xy)
=2xy-y+y-xy
=xy
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