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来源:百度文库 编辑:高校问答 时间:2024/04/30 09:19:12
已知:x-xy=20,xy-y=12,求代数式x-y,x+y-2xy的值.
x-y
=(x-xy)+(xy-y)
=20+12
=32
x+y-2xy
=(x-xy)-(xy-y)
=20-12
=8
x-y=(x-xy)+(xy-y)=20+12+32
x+y-2xy=(x-xy)-(xy-y)=20-12=8
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来源:百度文库 编辑:高校问答 时间:2024/04/30 09:19:12
x-y
=(x-xy)+(xy-y)
=20+12
=32
x+y-2xy
=(x-xy)-(xy-y)
=20-12
=8
x-y=(x-xy)+(xy-y)=20+12+32
x+y-2xy=(x-xy)-(xy-y)=20-12=8