1+1/(x+2)+1+1/(x+3)=1+1/(x+4)+1+1/(x+1)1/(x+2)+1/(x+3)=1/(x+4)+1/(x+1)1/(x+3)-1/(x+4)=1/(x+1)-1/(x+2)1/(x+3)(x+4)=1/(x+1)(x+2)(x+1)(x+2)=(x+3)(x+4)x²+3x+2=x²+7x+12x=-5/2检验：x=-5/2是方程的...