SOLUTION: given two terms in an arithmetic sequence, find the explicit formula http://prntscr.com/scu2dm

There are 30-16 = 14 gaps between the terms   and  .


Each gap is   = 7 units long.


So, the 16-th term of the arithmetic progression is   = 105,  and the common difference is  d = 7.


Now you can find the first term from the equation

     =  + 7*15,

    105 =  + 105

     = 0.


Hence, the formula for the general term is


     =  + d*(n-1) = 0 + 7*(n-1) = 7*(n-1).