Respuesta :

The explicit formula for an arithmetic sequence is  an = a1 +  d(n - 1)   where a1 is the first term and d = common difference.  For this sequence  a1 is 7 and  d =  13- 7 = 19 - 13 = 25 - 19 = 6

So explicit formula required = 7 + 6(n - 1)