What is a formula for vertex?

The vertex of a quadratic function in the form (y = ax^2 + bx + c) can be found using the formula (x = -\frac{b}{2a}) for the x-coordinate. To find the y-coordinate, substitute this x-value back into the original equation. Thus, the vertex is given by the point (\left(-\frac{b}{2a}, f\left(-\frac{b}{2a}\right)\right)). This point represents the maximum or minimum of the quadratic function, depending on the sign of (a).