1、最简公分母是abc
x/ab=cx/abc
y/bc=ay/abc
2、最简公分母是：4b²d
∴2c/bd=8bc/4b²d
3ac/4b²=3acd/4b²d
3、最简公分母是ab(x+2)
x/a(x+2)=bx/ab(x+2)
y/b(x+2)=ay/ab(x+2)
4、最简公分母是(x+y)²(x-y)
2xy/(x+y)²=2xy(x-y)/(x+y)²(x-y)
x/(x²-y²)=x(x+y)/(x+y)²(x-y)
1、最简公分母是abc
x/ab=cx/abc
y/bc=ay/abc
2、最简公分母是：4b²d
∴2c/bd=8bc/4b²d
3ac/4b²=3acd/4b²d
3、最简公分母是ab(x+2)
x/a(x+2)=bx/ab(x+2)
y/b(x+2)=ay/ab(x+2)
4、最简公分母是(x+y)²(x-y)
2xy/(x+y)²=2xy(x-y)/(x+y)²(x-y)
x/(x²-y²)=x(x+y)/(x+y)²(x-y)