1. **State the problem:** Write the quadratic equation $$y = -\frac{7}{4}x^2 - \frac{1}{2}x + 2$$ in vertex form, and identify the vertex, direction of opening, and y-intercept.
2. **Recall the vertex form of a quadratic:**
$$y = a(x - h)^2 + k$$
where $(h,k)$ is the vertex.
3. **Complete the square:**
Start with
$$y = -\frac{7}{4}x^2 - \frac{1}{2}x + 2$$
Factor out the coefficient of $x^2$ from the first two terms:
$$y = -\frac{7}{4}\left(x^2 + \cancel{\frac{1}{2} \div -\frac{7}{4}}x\right) + 2$$
Calculate the factor inside:
$$\frac{-\frac{1}{2}}{-\frac{7}{4}} = \frac{-0.5}{-1.75} = \frac{2}{7}$$
So rewrite:
$$y = -\frac{7}{4}\left(x^2 + \frac{2}{7}x\right) + 2$$
4. **Find the term to complete the square:**
Take half of $\frac{2}{7}$ and square it:
$$\left(\frac{1}{7}\right)^2 = \frac{1}{49}$$
Add and subtract inside the parentheses:
$$y = -\frac{7}{4}\left(x^2 + \frac{2}{7}x + \frac{1}{49} - \frac{1}{49}\right) + 2$$
5. **Rewrite as a perfect square and simplify:**
$$y = -\frac{7}{4}\left(\left(x + \frac{1}{7}\right)^2 - \frac{1}{49}\right) + 2$$
Distribute:
$$y = -\frac{7}{4}\left(x + \frac{1}{7}\right)^2 + \frac{7}{4} \times \frac{1}{49} + 2$$
Calculate:
$$\frac{7}{4} \times \frac{1}{49} = \frac{7}{196} = \frac{1}{28}$$
So:
$$y = -\frac{7}{4}\left(x + \frac{1}{7}\right)^2 + \frac{1}{28} + 2$$
Convert 2 to $\frac{56}{28}$:
$$y = -\frac{7}{4}\left(x + \frac{1}{7}\right)^2 + \frac{57}{28}$$
6. **Identify the vertex:**
The vertex is at $$\left(-\frac{1}{7}, \frac{57}{28}\right)$$
7. **Direction of opening:**
Since $a = -\frac{7}{4} < 0$, the parabola opens downwards.
8. **Find the y-intercept:**
Set $x=0$:
$$y = -\frac{7}{4}(0)^2 - \frac{1}{2}(0) + 2 = 2$$
So the y-intercept is at $(0, 2)$.
**Final answer:**
$$y = -\frac{7}{4}\left(x + \frac{1}{7}\right)^2 + \frac{57}{28}$$
Vertex: $$\left(-\frac{1}{7}, \frac{57}{28}\right)$$
Direction: Downwards
Y-intercept: $(0, 2)$
Vertex Form A87Ef7
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