A rectangle has one corner in quadrant I on the graph of y = 9 − x^2,another corner at the origin, and corners on both the positive y-axis and the positive x-axis. As the corner on

Question

y = 9 − x2 changes, a variety of rectangles are obtained.

Express the area A of the rectangles as a function of x.

Answer 1

clearly, each rectangle with upper-right corner at (x,y) has area

a = xy

Since y = 9-x^2, the area is just

a = x(9-x^2)

Not sure what you need to do with that information. The question is a bit vague.