1. **Problem Statement:** Given the graph of a polynomial function with local extrema at approximately $x=-9$, $x=-6$, $x=-2$, $x=3$, and $x=7$, answer the following:
(a) Identify intervals where the function is increasing.
(b) Find the $x$-values of local maxima.
(c) Determine the sign of the leading coefficient.
(d) Determine possible degrees of the polynomial.
2. **Key Concepts:**
- A function is increasing where its graph goes upward as $x$ increases.
- Local maxima occur at points where the function changes from increasing to decreasing.
- The leading coefficient sign affects end behavior: positive means the right end goes to $+\infty$, negative means it goes to $-\infty$.
- Degree parity and leading coefficient sign determine end behavior.
3. **Analyze intervals for increasing behavior:**
- From $-\infty$ to $-9$: graph rises \(\Rightarrow\) increasing.
- From $-9$ to $-6$: graph falls \(\Rightarrow\) decreasing.
- From $-6$ to $-2$: graph rises \(\Rightarrow\) increasing.
- From $-2$ to $3$: graph falls \(\Rightarrow\) decreasing.
- From $3$ to $7$: graph rises \(\Rightarrow\) increasing.
- From $7$ to $\infty$: graph falls \(\Rightarrow\) decreasing.
So increasing intervals are $$(-\infty,-9), (-6,-2), (3,7)$$
4. **Local maxima occur where function changes from increasing to decreasing:**
- At $x=-9$ (rises then falls)
- At $x=-2$ (rises then falls)
- At $x=7$ (rises then falls)
So local maxima at $$x=-9,-2,7$$
5. **Sign of leading coefficient:**
- The graph falls to bottom-left and falls to bottom-right.
- Both ends go down \(\Rightarrow\) leading coefficient is negative.
6. **Possible degree of the polynomial:**
- Since both ends fall, degree must be even and leading coefficient negative.
- Possible degrees from options: 4, 6, 8 (all even)
- Odd degrees have opposite end behavior, so 5, 7, 9 are not possible.
**Final answers:**
(a) Increasing on $$(-\infty,-9), (-6,-2), (3,7)$$
(b) Local maxima at $$x=-9,-2,7$$
(c) Leading coefficient is negative.
(d) Possible degrees: $$4,6,8$$
Polynomial Graph Bdb0B5
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