The function f (x) = - x2+40x-175

f (x) = - x2+40x-175

is graphed in the xy

xy

-plane above. For what value of x

x

is the value of f (x)

f (x)

greatest?

Answer: The maximum value of f (x) is when x = 225.

The equation given is an upside down parabola. Therefore, the maximum height of the parabola is at the vertex.

To find the vertex when the equation is in standard from, we can use "-b/2a" to find the x-value.

Our expression is:

-40/-2 = 20