Here, First term = a = 5

Common difference = d = 9/2 - 5 = - (1/2)

To find = 25^th term, ∴ n = 25

Using the formula for finding n^th term of an A.P.,

a_n = a + (n - 1) × d

∴ a_n = 5 + (25 - 1) × (-1/2)

⇒ a_n = 5 + 24 × (-1/2) = 5 - 12 = - 7

∴ 25^th term of the given AP is - 7.