The correct answers are: 1/2, 2 and -2.
To get this, factor f(x)
f(x)=2x^3-x^2-8x+4
f(x)= (2x^3-x^2) - (8x -4)
f(x)= (2x-1)(x^2) + (2x-1)(-4)
f(x)= (2x-1)(x^2-4)
f(x)= (2x-1)(x-2)(x+2)
2x-1=0
2x=1
x=1/2
x-2=0
x=2
x+2=0
x=-2
Sorry dont know, any thing else you need help with?
Remember that the volume of a cylinder is

so we have that
![r=\sqrt[]{\frac{V}{\pi\cdot h}}=\sqrt[]{\frac{1909.92384}{3.14\cdot6.6}}=\sqrt[]{92.12}=9.6](https://tex.z-dn.net/?f=r%3D%5Csqrt%5B%5D%7B%5Cfrac%7BV%7D%7B%5Cpi%5Ccdot%20h%7D%7D%3D%5Csqrt%5B%5D%7B%5Cfrac%7B1909.92384%7D%7B3.14%5Ccdot6.6%7D%7D%3D%5Csqrt%5B%5D%7B92.12%7D%3D9.6)
so the radius is 9.6 milimeters