\(\frac{7x+8}{21}-\frac{x+4}{8x-11}=\frac{x}{3}\left(x\ne\frac{11}{8}\right)\)
\(\Leftrightarrow\frac{\left(7x+8\right)\left(8x-11\right)}{21\left(8x-11\right)}-\frac{21\left(x+4\right)}{21\left(8x-11\right)}=\frac{7x\left(8x-11\right)}{21\left(8x-11\right)}\)
\(\Rightarrow56x^2-13x-88-21x-84=56x^2-77x\)
\(\Leftrightarrow43x=172\Leftrightarrow x=4\left(th\text{ỏa}m\text{ãn}\right)\)
Vậy x=4 là nghiệm của phương trình