Prove Big O notation with log

Question

I need to prove $$ 2n^2+5n+20log(n)=O(n^2) $$

I know that the right needs change term to the greatest degree I got: $$ 2n^2+5n+20log(n)≤2n^2+5n^2+... $$

I want to how to deal with the log

Answer 1

Perhaps a (logarithmic) graph will help: