Which polynomial function has the highest degree?

the quotient of f(x) and g(x), where f(x) = x9 – 3x and g(x) = 3x2 – 4

the product of f(x) and g(x), where f(x) = x2 – 3x and g(x) = 2x2 + 1

f(x) + g(x), where f(x) = x5 – 3x4 and g(x) = –x5 – 6x4 + 7

f(x) – g(x), where f(x) = x5 – 3x4 and g(x) = –3x5 + 2x4 + 1