Respuesta :

TheBilogis
Finding the parabolas roots.
-x^2+4x=0
-x(x-4)=0
x=0 and x=4

[tex] \int\limits^4_0 {(-x^2+4x)} \, dx [/tex]
[tex][-x^3/3+2x^2][/tex] (top is 4 and bottom is 0)
-64/3+32=32/3

The area above the x axis is 32/3