The function f(x) = -(x - 3)2 + 9 can be used to represent the area of a rectangle with a perimeter of 12 units, as a
function of the length of the rectangle, x. What is the maximum area of the rectangle?
3 square units
6 square units
9 square units
12 square units
The function f(x) describes a parabola opening downward, with a vertex at (3, 9). The maximum value of f(x) is found at the vertex, where it is f(3) = 9.
