6/(x^2-25)=3/(x^2+8x+15)+5/(x^2-2x-15)6/[(x-5)(x+5)]=3/[(x+3)(x+5)]+5/[(x+3)(x-5)]6(x+3)=3(x-5)+5(x+5)6x+18=3x-15+5x+256x+18=8x+106x+18-8x-10=0-2x+8=0x=4经检验,x=4是原方程的根.