1. **State the problem:** We are given the function $f(x) = x^2 - 4x$ and want to analyze it.
2. **Formula and rules:** This is a quadratic function of the form $ax^2 + bx + c$ where $a=1$, $b=-4$, and $c=0$.
3. **Find the vertex:** The vertex of a parabola $y = ax^2 + bx + c$ is at $x = -\frac{b}{2a}$.
4. **Calculate vertex x-coordinate:**
$$x = -\frac{-4}{2 \times 1} = \frac{4}{2} = 2$$
5. **Calculate vertex y-coordinate:**
$$f(2) = (2)^2 - 4(2) = 4 - 8 = -4$$
6. **Vertex point:** The vertex is at $(2, -4)$.
7. **Find x-intercepts:** Set $f(x) = 0$:
$$x^2 - 4x = 0$$
Factor:
$$x(x - 4) = 0$$
So, $x=0$ or $x=4$.
8. **Find y-intercept:** Set $x=0$:
$$f(0) = 0^2 - 4(0) = 0$$
So, y-intercept is at $(0,0)$.
9. **Summary:** The parabola opens upwards (since $a=1>0$), vertex at $(2,-4)$, x-intercepts at $(0,0)$ and $(4,0)$, and y-intercept at $(0,0)$.
**Final answer:** The function $f(x) = x^2 - 4x$ has vertex at $(2,-4)$ and roots at $x=0$ and $x=4$.
Quadratic Function 395528
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