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

Vertex form: f(x) = x^2 - 18x + 60 = (x - 9)^2 - 21, so the vertex is (9, -21).

Check statements:
- x-coordinate > y-coordinate: 9 > -21, true.
- x-coordinate negative: 9 is not negative, false.
- y-coordinate > y-intercept: -21 > 60 (y-intercept = f(0)=60), false.
- y-coordinate positive: -21 is not positive, false.

So the true statement is: The x-coordinate of the vertex is greater than the y-coordinate.