## Growth of Functions Problem

Hey could anyone assist me with this problem?

Find the least integer $n$ such that $f(x)$ is $O(x^n)$ for each of these functions.

a) $f(x) = 2x^2+x^3logx$
b) $f(x) = 3x^5+(logx)^4$
c) $f(x) = (x^4+x^2+1)/(x^4+1)$
d) $f(x) = (x^3+5logx)/(x^4+1)$