9 A curve has equation
$$y = \mathrm { e } ^ { 3 x } - 5 \mathrm { e } ^ { 2 x } + 8 \mathrm { e } ^ { x }$$
- Find the exact coordinates of the stationary points of \(y\).
- Determine the range of values of \(x\) for which
$$\frac { \mathrm { d } ^ { 2 } y } { \mathrm {~d} x ^ { 2 } } > 0$$
- Determine the nature of the stationary points on the curve.