Please solve 14th question 

$\mathbf{14}\mathbf{.} Solve : {\tan }^{-1} \frac{32}{43} + {\tan }^{-1}\frac{1}{6} + {\tan }^{-1} \frac{1}{x} = \raisebox{1ex}{$\mathrm{\pi }$}\!\left/ \!\raisebox{-1ex}{$4$}\right.$