I am getting a bit confused here.. the question asks to find the volume of the solid that results from rotating $\displaystyle y^2=8x, x=2 $ around the line $\displaystyle x=4$.

My setup is this: $\displaystyle 2 \pi \int_{-4}^4(2-x)(\sqrt{8x}) dx$

but when i integrate and substitute i cant get values for the negative lower limit.. what's my error?