The correct answer is:

B. Find the vertex. The y-coordinate of the vertex is the minimum or maximum value depending on whether the graph opens upward or downward.

Explanation:

In the case of a quadratic function $f(x) = ax^2 + bx + c$, the maximum or minimum value occurs at the vertex of the parabola. The y-coordinate of the vertex represents this value:

• If $a > 0$ (the parabola opens upwards), the vertex gives the minimum value.
• If $a < 0$ (the parabola opens downwards), the vertex gives the maximum value.

Would you like further explanation on this or have more questions?

Here are five related questions for practice:

1. How do you find the x-coordinate of the vertex using the formula $x = -\frac{b}{2a}$?
2. What happens to the vertex if the quadratic function is shifted vertically?
3. Can the vertex ever be the x-intercept of the quadratic function?
4. How does the value of $a$ affect whether the vertex is a maximum or minimum?
5. How do you find the axis of symmetry from a quadratic function?

Tip: In the vertex form of a quadratic function, $f(x) = a(x - h)^2 + k$, the vertex is directly given as $(h, k)$, and the y-coordinate $k$ is the maximum or minimum value.