1. **State the problem:** We analyze the function $f$ given by a parabola opening upwards with vertex at $(4,-1)$, x-intercepts at $x=2$ and $x=6$, and y-intercept at $y=8$.
2. **Domain:** The domain of any parabola is all real numbers, so the domain is $$(-\infty, \infty).$$
3. **Range:** Since the parabola opens upwards and the vertex is the minimum point at $y=-1$, the range is $$[-1, \infty).$$
4. **X-intercepts:** The parabola crosses the x-axis where $f(x)=0$. Given intercepts at $x=2$ and $x=6$, the x-intercepts are $$2 \text{ and } 6.$$
5. **Y-intercept:** The parabola crosses the y-axis at $x=0$. Given $f(0)=8$, the y-intercept is $$8.$$
6. **Intervals of increase and decrease:**
- The vertex is at $x=4$.
- For $x<4$, the parabola is decreasing.
- For $x>4$, the parabola is increasing.
So,
- Increasing on $$(4, \infty)$$
- Decreasing on $$(-\infty, 4)$$
7. **Intervals where $f$ is constant:** A parabola is never constant on any interval, so there are none.
8. **Relative minimum:** The vertex at $x=4$ is the relative minimum point.
- The relative minimum value is $$f(4) = -1.$$
9. **Evaluate $f(-2)$:** Since the parabola passes through $(0,8)$ and has vertex $(4,-1)$, we can find $f(-2)$ by using the quadratic formula or symmetry.
The parabola has roots at $2$ and $6$, so it can be written as $$f(x) = a(x-2)(x-6).$$
Using the vertex $(4,-1)$:
$$-1 = a(4-2)(4-6) = a(2)(-2) = -4a \implies a = \frac{1}{4}.$$
So,
$$f(x) = \frac{1}{4}(x-2)(x-6) = \frac{1}{4}(x^2 - 8x + 12).$$
Calculate $f(-2)$:
$$f(-2) = \frac{1}{4}((-2)^2 - 8(-2) + 12) = \frac{1}{4}(4 + 16 + 12) = \frac{32}{4} = 8.$$
10. **Solve $f(x) = 3$:**
$$\frac{1}{4}(x^2 - 8x + 12) = 3 \implies x^2 - 8x + 12 = 12.$$
Simplify:
$$x^2 - 8x + 12 - 12 = 0 \implies x^2 - 8x = 0.$$
Factor:
$$x(x - 8) = 0 \implies x = 0 \text{ or } x = 8.$$
11. **Even, odd, or neither:**
- Check $f(-x)$:
$$f(-x) = \frac{1}{4}((-x)^2 - 8(-x) + 12) = \frac{1}{4}(x^2 + 8x + 12).$$
- Compare with $f(x)$:
$$f(x) = \frac{1}{4}(x^2 - 8x + 12).$$
Since $f(-x) \neq f(x)$ and $f(-x) \neq -f(x)$, the function is **neither even nor odd**.
**Final answers:**
- (a) Domain: $$(-\infty, \infty)$$
- (b) Range: $$[-1, \infty)$$
- (c) X-intercepts: $$2, 6$$
- (d) Y-intercept: $$8$$
- (e) Increasing on $$(4, \infty)$$
- (f) Decreasing on $$(-\infty, 4)$$
- (g) Constant on $$\varnothing$$ (none)
- (h) Relative minimum at $$x=4$$
- (i) Relative minimum value: $$-1$$
- (j) $f(-2) = 8$
- (k) $f(x) = 3$ at $$x=0, 8$$
- (l) Function is **neither even nor odd**.
Parabola Analysis D2C9D0
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