Question

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.

Answer 1

While it might be a little more work, why not actually convert the equation f(x) = x2 – 18x + 60 to vertex form? Vertex form looks like \[y=a(x-h)^2+k\]

Answer 2

...where (h,k) is the vertex.

Answer 3

The attached plot might help.