They are functions because they have the variables
Given: <span>y = x^2 + 6x - 5. Then a = 1, b = 6 and c = -5.
The x-coord. of the vertex is given by x = -b / (2a), which here is x = -6 / (2*1) = -3.
Use the given formula </span><span>y = x^2 + 6x - 5 to find the value of y when x = -3:
y = (-3)^2 + 6(-3) - 5 = 9 - 18 - 5 = -14
Then the vertex is (-3, -14).</span>
Yup! We're all pretty good here.
