Area between two curves:

y=9-x^2

y=x^2 - 7

Show that the area is (128√2)/3

So...

y=9-x^2

y'=-2x

I(x) = 9x - (1/3)x^3

y=x^2 - 7

y'=2x

I(x) = (1/3)x^3 - 7x

9 - x^2 = x^2 - 7

x = √8

Correct so far? What next? How can I make it to find the correct area? Thanks!