Area by integration(How to find length and area?)?

Question

Guys the question is clear, but here is the image that I graph, hope it help's

http://img153.imageshack.us/my.php?image=integrationve5.jpg

Find the the area bounded by the curve y=9-x^2 and the x-axis

Answer 1

The length of the rectangle is y, which is equal to 9 - x².

Ergo,

dA = (9-x²)dx and

A = ∫(9-x²)dx = [9x - x³/3] = 36 for -3<x<3