1- (1 + 0.12/12) -12(30) xponent. i am trying to simplify this and i do not understand? this is how to find the monthly payment of:

consider a student loan of $25,000 at a fixed apr of 12% for 30 years.
a. calculate the monthly payment.
b. determine the total amount paid over the term of the loan.
c. of the total amount paid, what percentage is paid toward the principal and what percentage is paid for