Question

 If the sum of the first ‘n’ terms of an A.P. is 5n + n^2 then find its 10th term​

Answer 1

Answer:

a10 = 24

Step-by-step explanation:

sum of n terms = 5n + n²

first term = s1 = a1

a1 = 5(1) + 1²

= 5 + 1

= 6

sum of two terms = s2 = a1 + a2

= 5(2) + 2²

= 10 + 4

= 14

a1 + a2 = 14

6 + a2 = 14

a2 = 14 - 6

a2 = 8

d = a2 - a1

d = 8 - 6

d = 2

10th term = a + (n - 1) d

a10 = 6 + (10 - 1)(2)

a10 = 6 + (9 × 2)

a10 = 6 + 18

a10 = 24

Hope you get your answer