1. **Problem statement:** We need to sketch a quartic polynomial function $y = f(x)$ such that $f(x) > 0$ when $x < -5$, $2 < x < 3$, and $x > 4$. We also need to write an inequality statement for this function.
2. **Understanding the problem:** A quartic polynomial is degree 4, so it can have up to 4 real roots. The function is positive in three intervals: $(-\infty, -5)$, $(2, 3)$, and $(4, \infty)$. This means the function crosses the x-axis at points that separate these intervals where the sign changes.
3. **Determining roots:** The roots must be at $x = -5$, $x = 2$, $x = 3$, and $x = 4$ to create the intervals where $f(x)$ changes sign.
4. **Sign analysis:** Since $f(x) > 0$ for $x < -5$, the polynomial is positive to the left of $-5$. The sign changes at each root, so the intervals between roots alternate signs.
5. **Constructing the polynomial:** The roots are $-5$, $2$, $3$, and $4$. The polynomial can be written as:
$$f(x) = a(x + 5)(x - 2)(x - 3)(x - 4)$$
6. **Determining leading coefficient $a$:** Since $f(x) > 0$ for $x < -5$, and the degree is even, the ends of the graph go to $+\infty$ if $a > 0$. So choose $a > 0$.
7. **Inequality statement:** The function is positive in the intervals $x < -5$, $2 < x < 3$, and $x > 4$. So the inequality is:
$$f(x) > 0 \text{ for } x < -5, \quad 2 < x < 3, \quad \text{and} \quad x > 4$$
8. **Summary:** The quartic polynomial is
$$f(x) = a(x + 5)(x - 2)(x - 3)(x - 4), \quad a > 0$$
and the inequality describing where $f(x)$ is positive is
$$f(x) > 0 \text{ for } x < -5, \quad 2 < x < 3, \quad x > 4.$$
Quartic Inequality 295265
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