1. the fifth, ninth and sixteenth terms of a linear sequence [a.p] are consecutive terms of an exponential sequence[g.p]. (a).find the common difference of the linear sequence in terms of the first term. (b). show that the twenty-first, thirty-seventh and sixty-fifth terms of the linear sequence are consecutive terms of an exponential sequence whose common ration is 7/4. (2). (a). find the number of terms of the linear sequence [ap] 4,6½,9, 11½... required to make a sum of 126. (b).if the 1st and 3rd terms of the a.p in [a] are also the 1st and 3rd terms of a geometric progression [g.p],find the common ratio.​