[问答题]
$\text { Let } f(x)=x^{3}+3 x^{2}-9 x+k \text {. Part of the graph of } f \text { is shown below. The graph of } f \text { has a local maximum at } \mathrm{A} \text {, a local minimum at } \mathrm{B} \text { and a point of inflection at } \mathrm{C} \text {. }$
1. 1. Find $f^{\prime}(x)$ .
2. Find $f^{\prime \prime}(x)$ .
2. Find the x -coordinate of the point of inflection at C .
Given that f(-1)=14 .
3. 1. Find f(0) .
2. Hence, find the coordinates of the local maximum $\mathrm{A}(x, y)$ and justify your answer.
4. Write down in order from least to greatest $f^{\prime \prime}(\mathrm{B})$, $f^{\prime}(\mathrm{B}), f(\mathrm{~B})$ .v
