I have been given the question. Show that f(n) = ((n^3)+(7n^2))/(n^2 - 14) = O(n)

I know how to prove for a general

//Linear Function

//Consider f(n) = 5n + 4. When n >= 4,

//5n + 4 <= 5n + n <= 6n.

//So f(n) = O( n ) [i.e., c = 6 and n0 = 4].

but this question baffles me, please anyone help :(