Find the 6th and 15th terms of the a.p whose first terms is 6 and common different is 6

a=6 , d = 6

term(6) = a + 5d = 6 + 5(6) = 6 + 30 = 36
term(15) = a + 14d = ...

btw, it is "common difference" , not "common different"