F(x) =8+2x and g(x) =1/2x the value of f/g(5)

Which expression is not a polynomial?

Carley bought a jacket that was discounted 10% off the original price. the expression below represents the discounted price in dollars, based on x, the original price of the jacket.

Prove that (x-2)is factor of p (x)=2x³-3x²-17x+30