已知x+y=4,xy=3,求4{xy+2y}+{6x-[2xy-y-3x}}的值 x+y=-4

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已知x+y=4,xy=3,求4{xy+2y}+{6x-[2xy-y-3x}}的值 x+y=-4

已知x+y=4,xy=3,求4{xy+2y}+{6x-[2xy-y-3x}}的值 x+y=-4
已知x+y=4,xy=3,求4{xy+2y}+{6x-[2xy-y-3x}}的值
x+y=-4

已知x+y=4,xy=3,求4{xy+2y}+{6x-[2xy-y-3x}}的值 x+y=-4
原式=4xy+8y+6x-2xy+y+3x
=2xy+9x+9y
=2xy+9(x+y)
=6+36
=42

4{xy+2y}+{6x-[2xy-y-3x]}=4XY+8Y+6X-2XY+Y+3X=2XY+9(X+Y)=2*3+9*4=42

原式=4xy+8y+6x-2xy+y-3x
=2xy+9x+9y
=2xy+9(x+y)
把x+y=4,xy=3,代入上式2xy+9(x+y)=2×3+9×4=42
把x+y=-4,xy=3,代入上式2xy+9(x+y)=2×3+9×(-4)=-30

原式=4(3+2y)+(6x-[6-y-3x])
=12+8y+6x-6+y+3x
=6+9x+9y=6+9(x+y)=6+9*4=42

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