Given two terms in artimetic sequence find the common difference, the 52 term, and the explicit formula. A15=139 and A30=259

139, 149, 159, 169, 179, 189, 199, 209, 219, 229, 239, 249, 259.

The common difference is 13.

Let n = 52

Let d = common difference

a_52 = 139 + (52 - 1) (13)

a_52 = 139 + (51) (13)

a_52 = 139 + 663

a_52 = 802