Simplify (7^3)^8 its a question i dont understand what to do asap

Determine the quotient of the following expression. (15n^2-27n) / 3

A) if $50000 is invested in a bank account that pays 9.3% of interest compounded on a six-monthly basis, how much money will be in the account after 3 and 12 years? b) if matusalen's father had put $2.0 in the bank when he was born and there, how long would matusalen have had to his death (969 years later) if the interest was 7% per year composed each month and weekly?

Which is greater, 7 p 5 or 7 c 5? 7p5 7c5