The sum of the first n terms of an AP is 3n^2 + 2n. Find the sum of its first 10 terms, and also find its 10th term. Which pair of values is correct?

Question

Accepted Answer

Sum = 320, 10th term = 59. S_10 = 3(100)+2(10) = 320. a_10 = S_10 - S_9 = 320 - (3(81)+2(9)) = 320 - (243+18) = 320 - 261 = 59.

The sum of the first $n$ terms of an AP is $3 n^{2} + 2 n$ .
Find the sum of its first 10 terms, and also find its 10th term.
Which pair of values is correct?