初二分式通分题，急！谢

x/(x+y),(x+y)/(x^2-xy)

1/(6x-4y),2/(9x^2-4y^2)

1/(x+y)(y+z),1/(y+z)(x+z)

b/a(x+1)(2-x),a/b(1-x)(x-2)

x/(x+y),(x+y)/(x^2-xy)

x^2-xy=x(x-y)

公分母:x(x+y)(x-y)

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1/(6x-4y),2/(9x^2-4y^2)

6x-4y=2(3x-2y)

9x^2-4y^2=(3x+2y)(3x-2y)

公分母:2(3x+2y)(3x-2y)

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1/(x+y)(y+z),1/(y+z)(x+z)

公分母:(x+y)(y+z)(x+z)

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b/a(x+1)(2-x),a/b(1-x)(x-2)

a(x+1)(2-x)=-a(x+1)(x-2)

b(1-x)(x-2)=-b(x-1)(x-2)

公分母:ab(x+1)(x-1)(x-2)