30/x - 30/(x+3) = 0.5两边同乘以2x(x+3),得60(x+3)-60x=x(x+3)x²+3x-180=0(x-12)(x+15)=0x=12或x=-15经检验都是方程的根.2x/x+1=1-x/3x+3两边同乘以3(x+1)6x=1-x7x=1x=1/7经检验是方程的根....