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

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

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

若x-y=5,-xy=3,求(7x+4y+xy)-6(6分之5y+x-xy)的值
(7x+4y+xy)-6(6分之5y+x-xy)
=7x+4y+xy-5y-6x+6xy
=(7-6)x+(4-5)y+(1+6)xy
=x-y+7xy
若x-y=5,-xy=3,则x-y+7xy=-16.
因为-xy=3,不是xy=3所以最后等于-16.

(7x+4y+xy)-6(6分之5y+x-xy)
=7x+4y+xy-5y-6x+6xy
=x-y+7xy
=5+7*3
=26

(7x+4y+xy)-6(6分之5y+x-xy)
=7x+4y+xy-5y-6x+6xy
=x-y+7xy
=5+7*3
=26