Degree 4 means you'll have x^4 as your leading term. Multiplicity of 3 means you have the same factor 3 times. So if x = -2, then (x + 2) = 0, so (x + 2) is used 3 times. FOIL that out 3 times and you get x^3 + 6x^2 + 12x + 8. Now multiply by (x + 0) to get a 4th degree polynomial of x^4 + 6x^3 + 12x^2 + 8x. There!
