Question

I did A and B I just need help with the rest!

Answer 1

Solution

(a) setting f(x) = 0

$\begin{gathered} 3x^4-18x^3-21x^2+144x-108=0 \\ \\ (x+3)(x-1)(x-2)(x-6)=0 \\ \\ \Rightarrow x=-3,1,2,6 \end{gathered}$

(b)

when x = 0

y = f(0) = -108

Hence, the height is 108

(c)

Maximum = (1.5, 15.188)

(d)

Minimum (-1.702, -300) and (4.702, -300)

(e) From the graph, the interval of increasing is

$\begin{gathered} (-1.7,\frac{3}{2}),(4.7,\infty) \\ \end{gathered}$

(f) From the graph, the interval of decreasing is;

$(-\infty,-1.7),(\frac{3}{2},4.7)$

g)