Just wanted to check that this proof is set out correctly and that the last statement is logically correct:
AnswerUse mathematical induction to prove that is divisible by 15 for all positive integers n.
Let be is divisible by 15.
Assuming to be true  ( ),
Therefore if is divisible by 15, then so is ,
When , . Therefore the basis case holds true.
Therefore by mathematical induction,
I was like ooh that looks interesting then saw that it's 112 pages long. I'll keep it until next week when my exams are over.
Thank you though.
Edit. Oh you said page 9. Brain is melting from too much maths sorry