解最简公分母为(x-y)(x+y)∴1/(x-y)=(x+y)/(x-y)(x+y)=(x+y)/(x²-y²)1/(x+y)=(x-y)/(x-y)(x+y)=(x-y)/(x²-y²)最简公分母为：6a²bc∴a/2b=3a³c/(6a²bc)1/3a²=2bc/(6a²bc)-5/6abc=-5a/(6a²bc)
