Solve the following equation for `x :` `tan^(-1)(1/4)+2tan^(-1)(1/5)+tan^(-1)(1/6)+tan^(-1)(1/x)=pi/4`

Explanation

To solve the equation

\[ \tan^{-1}\left(\frac{1}{4}\right) + 2\tan^{-1}\left(\frac{1}{5}\right) + \tan^{-1}\left(\frac{1}{6}\right) + \tan^{-1}\left(\frac{1}{x}\right) = \frac{\pi}{4}, \]

we will use the following formulas for inverse tangent:

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