I am an undergraduate student in Computer Engineering and going through one of the textbook examples, I am asked to prove that $T(n)$ is $O(\log{}n)$Where $T(n)= 5\log_{2} 2n +7$.I understand that this means that I must prove that $5\log_{2} 2n +7 \leq\lambda log(n)$For some in n in a neighborhood of infinity. How exactly would I proceed with this? 
Big O Proof for Logarithmic Function
asymptotics;proof techniques