5/(x^+6x+2)+4/(x^+6x+8)=3/(x^+6x+1)

设Y=X^2+6X+1,于是原方程化为：5/(Y+1)+4/(Y+7)=3/Y,方程两边都乘以Y(Y+1)(Y+7),得：5Y(Y+7)+4Y(Y+1)=3(Y+1)(Y+7)5Y^2+35Y+4Y^2+4Y=3Y^2+24Y+21,6Y^2+15Y-21=02Y^2+5Y-7=0(2Y+7)(Y-1)=0Y=1或-7/2,当Y=1,即X^2+6X+1=1...