Question

If a=-5 and d= 3 and sn=110 find nth term

Answer 1

Answer:

answer for the given problem is given

Answer 2

Given , a= -5

d= 3

Sn = 110

=> (n/2) {2a + (n-1)d} = 110

=> (n/2) { 2×(-5) + (n-1)3 } =110

=> (n/2) { (-10) + 3n - 3} = 110

=> n( 3n- 13) = 110×2

=> 3n^2 - 13n - 220 =0

=> 3n^2 - 33n +20n - 220 =0

=> 3n( n - 11) + 20(n -11) =0

=> (3n + 20)(n - 11) =0

So ,

3n-20 = 0

=> 3n = 20

=> n = 20/3

{not expectable}

or n-11 =0

=> n = 11

Therefore

N = 11