If $A$ is a non-singular matrix and $A^2 - A + I = 0$, then $A^{-1} = \ldots$

The value of $3\tan^{-1}\left(\dfrac{1}{2}\right) = \ldots$

If $f(x) = \dfrac{x+2}{x^2-3x+1}$, then the values of $x$ for which $f(x)$ is not defined are

If $f : R \to R$ and $g : R \to R$ are defined as $f(x) = 2x - |x|$ and $g(x) = 2x + |x|$, then