Charla wants to determine the vertex of the function f(x) = x2 – 18x + 60 by changing the function into vertex form. which statement about the vertex of the function is true?

the x-coordinate of the vertex is greater than the y-coordinate.
the x-coordinate of the vertex is negative.
the y-coordinate of the vertex is greater than the y-intercept.
the y-coordinate of the vertex is positive.

F(x) = x² - 18x + 60

numerical coefficients
a = 1    b = -18   c = 60

we strive to canonical form of a quadratic function
f(x) = a*(x-p)² +q

x ( cut ) the tip is marked p



We get the p-value for the pattern canonical function . The pattern now looks like this :
f(x) = a(x-p)² + q
f(x) = (x -9)² + q

Now we calculate the value of y ( ordinate) vertex functions designated letter q



as you can see we need a value of Δ

Δ = b² - 4ac = (-18)² - 4 * 1* 60 = 324 - 240 = 84



canonical form of the function now looks like
f(x) = (x - 9)² - 21

1 - truth  (9> (-21))
2 - lie  (9>0)
3 - lie  (-21 < 9)
4 - lie (- 21<0)