Quadratic Vertex Form
1. The problem asks to rewrite the quadratic function $f(x) = -2x^2 + 6x - 1$ in the vertex form $a(x+h)^2 + k$, where $a$, $h$, and $k$ are constants.
2. Start with the given function:
$$f(x) = -2x^2 + 6x - 1$$
3. Factor out the coefficient of $x^2$ from the quadratic terms:
$$f(x) = -2(x^2 - 3x) - 1$$
4. Complete the square inside the parentheses. To complete the square, take half of the coefficient of $x$, which is $-3$, so half is $-\frac{3}{2}$. Square it:
$$\left(-\frac{3}{2}\right)^2 = \frac{9}{4}$$
5. Add and subtract $\frac{9}{4}$ inside the parentheses to keep the expression equivalent:
$$f(x) = -2 \left(x^2 - 3x + \frac{9}{4} - \frac{9}{4}\right) - 1$$
6. Group the perfect square trinomial and the constant term:
$$f(x) = -2 \left(\left(x - \frac{3}{2}\right)^2 - \frac{9}{4}\right) - 1$$
7. Distribute $-2$:
$$f(x) = -2 \left(x - \frac{3}{2}\right)^2 + 2 \times \frac{9}{4} - 1 = -2 \left(x - \frac{3}{2}\right)^2 + \frac{9}{2} - 1$$
8. Simplify the constants:
$$\frac{9}{2} - 1 = \frac{9}{2} - \frac{2}{2} = \frac{7}{2}$$
9. The vertex form is therefore:
$$f(x) = -2 \left(x - \frac{3}{2}\right)^2 + \frac{7}{2}$$
Final answer: $f(x) = -2(x - \frac{3}{2})^2 + \frac{7}{2}$ where $a = -2$, $h = -\frac{3}{2}$, and $k = \frac{7}{2}$.