已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)]

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已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)]
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已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)]
已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)]

已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)]
原式=6xy+10y+4x-5xy-4y+2x
=6x+6y
=6(x+y)
=6×(-2)
=-12

(6xy+10y)+[4x-2(3xy+2y-x)]
原式=6xy+10y+4x-6xy-4y+2x
=6Y+6X
=6(X+Y)
把x+y=-2代入6(X+Y)=6×﹙-2﹚=-12

(6xy+10y)+[4x-2(3xy+2y-x)]
去括号,得
6xy+10y+4x-6xy-4y+2x
=6y+6x
=6(x+y)
把x+y= -2代入上式,得
6xy+10y+4x-6xy-4y+2x
=6y+6x
=6(x+y)
=6×(-2)
= -12

原式=6xy+10y+(4x-6xy-4y+2x)=6x+6y=6(x+y)=-12