Question

When you ARE NOT given the vertex from a graph, how do you find the k value?

Answer 1

Answer:

$f( - \frac{b}{2a} )$

Step-by-step explanation:

When you not given the vertex form, the you are given the standard form:

$f(x) = a {x}^{2} + bx + c$

The value of k, is the y-value of the vertex of the function.

To find the value of k, you plug in

$x = - \frac{b}{2a}$

In order works, you evaluate

$f( - \frac{b}{2a} )$

This will give you the k-value