Question

The sum of n terms of an AP is 3n² + 5n, find the 10th term​

Answer 1

Answer:

260

Step-by-step explanation:

let take n= 1,2,3,4.....

S1=8 means a=8

S2=22 from here we get d=28

now A10=260

Answer 2

Step-by-step explanation:

Now,sum of n terms = 3n²+5n

then,sum of 10 terms = 3(10)²+5(10)

=300+50 = 350

and, sum of 9 terms = 3(9)²+5(9)

=243+45 = 288

Now,the 10th term of A.P = (sum of 10 terms -

sum of 9 terms)

= 350-288 = 62