3.23: Rational squared curve: stationary points and $k$

Show that $y = \left(\dfrac{x}{x - 4}\right)^{2}$ can be written as $y = 1 + \dfrac{8}{x - 4} + \dfrac{16}{(x - 4)^{2}}$. Hence find the exact coordinates of the stationary points on the curve.

On the axes, sketch the graph of $y = \left(\dfrac{x}{x - 4}\right)^{2}$, stating the intercepts with the coordinate axes.

Find the possible values of $k$ for which $\left(\dfrac{x}{x - 4}\right)^{2} = k$ has exactly 4 different solutions.