The curve \(C\) has equation \(y=\frac{x+2}{x^{2}-9}\). Show that \(\frac{\mathrm{d} y}{\mathrm{~d} x}\lt 0\) at all points on \(C\).

State the equations of the asymptotes of \(C\).

Sketch \(C\), showing the coordinates of any points of intersection with the coordinate axes.