1/x(x+3)+1/(x+3)(x+6)+1/(x+6)(x+9)=[1/x-1/(x+3)+1/(x+3)-1/(x+6)+1(x+6)-1/(x+9)]/3=[1/x-1/(x+9)]/3=3/x(x+9)=3/2x+182x+18=x(x+9)x²+7x-18=0(x-2)(x+9)=0x1=2x2=-9(经检验知,不合舍去）所以,x=2是原分式方...