giải phương trình sau x+4/8+x+6/7=x-2/11+x-4/12

#andy

\[\begin{array}{l}
\dfrac{{x + 4}}{8} + \dfrac{{x + 6}}{7} = \dfrac{{x - 2}}{{11}} + \dfrac{{x - 4}}{{12}}\\
MC:1848\\
 \Leftrightarrow \dfrac{{231\left( {x + 4} \right)}}{{8.231}} + \dfrac{{264\left( {x + 6} \right)}}{{7.264}} = \dfrac{{168\left( {x - 2} \right)}}{{11.168}} + \dfrac{{154\left( {x - 4} \right)}}{{154.12}}\\
 \Leftrightarrow \dfrac{{231x + 924}}{{1848}} + \dfrac{{264x + 1584}}{{1848}} = \dfrac{{168x - 336}}{{1848}} + \dfrac{{154x - 616}}{{1848}}\\
 \Leftrightarrow 231x + 924 + 264x + 1584 = 168x - 336 + 154x - 616\\
 \Leftrightarrow 231x + 264x - 168x - 154x =  - 336 - 616 - 924 - 1584\\
 \Leftrightarrow 173x =  - 3460\\
 \Leftrightarrow x =  - 20
\end{array}\]