I NEED MAJOR HELP!(Question on Polynomials)

Ok so this is my tips question which is due tomorrow for marks and I havnt been able to think how to do it.

The Volume of a cylindrical can is

4(pi)x^3 + 28(pi)x^2 + 65(pi)x + 50(pi) cm^3. If the can has a height of

(x +2)cm, what is the radius of the cylinder? Now so far I figured the way to figure this out is to take the formula for Volume of a cylinder which is V=pi*r^2 *h and rearange is so your solving for r^2 instead so it would be r^2=(pi)(h)(V). The problem is im pretty sure I need to factor that equation out or expand w/e it is. I know how to expand out an equation where theres just x2 + x + 0 lets say but I dont know how to expand it when you have that extra x so its now x3 + x2 + x + 0. Can someone plz help me right now whoever's on at this time? Thanks!