若x-y=5,-xy=3,求(7x+4y+xy)-6(5/6y+x-xy)

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若x-y=5,-xy=3,求(7x+4y+xy)-6(5/6y+x-xy)
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若x-y=5,-xy=3,求(7x+4y+xy)-6(5/6y+x-xy)
若x-y=5,-xy=3,求(7x+4y+xy)-6(5/6y+x-xy)

若x-y=5,-xy=3,求(7x+4y+xy)-6(5/6y+x-xy)
你好:
原式=(7x+4y+xy)-(5y+6x-6xy) ……………………把“6”乘进去
=7x+4y+xy-5y-6x+6xy
=x-y+7xy
因为x-y=5,-xy=3
所以xy=-3
所以,原式=5+7乘以(-3)=-16

-xy=3
xy=-3
(7x+4y+xy)-6(5/6y+x-xy)
=7x+4y+xy-5y-6x+6xy
=x-y+7xy
=5+7×(-3)
=-16

(7x+4y+xy)-6(5/6y+x-xy)=x-y+7xy=5-21=-16