1\X-1\Y=3,求5X+XY-5Y\X-XY-Y的值.2-X\X-3=1\3-X -2(2X^2-4XY)\(X-2Y)=已知a^m=2,a^n=3,则a^m+n=___,a^2n=___若X^2+MXY+81Y^2是一个完全平方式,则M=___
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![1\X-1\Y=3,求5X+XY-5Y\X-XY-Y的值.2-X\X-3=1\3-X -2(2X^2-4XY)\(X-2Y)=已知a^m=2,a^n=3,则a^m+n=___,a^2n=___若X^2+MXY+81Y^2是一个完全平方式,则M=___](/uploads/image/z/226027-19-7.jpg?t=1%5CX-1%5CY%3D3%2C%E6%B1%825X%2BXY-5Y%5CX-XY-Y%E7%9A%84%E5%80%BC.2-X%5CX-3%3D1%5C3-X%26%23160%3B+-2%282X%5E2-4XY%29%5C%28X-2Y%29%3D%E5%B7%B2%E7%9F%A5a%5Em%3D2%2Ca%5En%3D3%2C%E5%88%99a%5Em%2Bn%3D___%2Ca%5E2n%3D___%E8%8B%A5X%5E2%2BMXY%2B81Y%5E2%E6%98%AF%E4%B8%80%E4%B8%AA%E5%AE%8C%E5%85%A8%E5%B9%B3%E6%96%B9%E5%BC%8F%2C%E5%88%99M%3D___)
1\X-1\Y=3,求5X+XY-5Y\X-XY-Y的值.2-X\X-3=1\3-X -2(2X^2-4XY)\(X-2Y)=已知a^m=2,a^n=3,则a^m+n=___,a^2n=___若X^2+MXY+81Y^2是一个完全平方式,则M=___
1\X-1\Y=3,求5X+XY-5Y\X-XY-Y的值.
2-X\X-3=1\3-X -2
(2X^2-4XY)\(X-2Y)=
已知a^m=2,a^n=3,则a^m+n=___,a^2n=___
若X^2+MXY+81Y^2是一个完全平方式,则M=___
1\X-1\Y=3,求5X+XY-5Y\X-XY-Y的值.2-X\X-3=1\3-X -2(2X^2-4XY)\(X-2Y)=已知a^m=2,a^n=3,则a^m+n=___,a^2n=___若X^2+MXY+81Y^2是一个完全平方式,则M=___
∵1/X-1/Y=3
∴X-Y=-3XY
∵5X+XY-5Y/X-XY-Y=[5(X-Y)+XY]/[(X-Y)-XY]
∴[5(-3XY)+XY]/(-3XY-XY)
即 原式=(-15XY+XY)/(-4XY)
=14XY/4XY
=3.5
(2-X)/(X-3)=1/(3-X)-2
(2-X)/(X-3)=-1/(X-3)-2
(2-X)/(X-3)=[-1-2(X-3)]/(X-3)
(2-X)/(X-3)=[5-2X]/(X-3)
(2-X)/(X-3)-[5-2X]/(X-3)=0
(2-X-5+2X)/(X-3)=0
(X-3)/(X-3)=0
方程无解
(2X^2-4XY)\(X-2Y)
=2X(X-2Y)/(X-2Y) (X≠2Y )
=2X
已知a^m=2,a^n=3,则a^m+n=___,a^2n=___
a^m+n=a^m*a^n=2*3=6
a^2n=(a^n)^2=3^2=9
若X^2+MXY+81Y^2是一个完全平方式,则M=___
(X±9Y)^2=X^2±18XY+81Y^2
M=±18
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