Question

In sequence what is nth term of 7,12,20..?

Answer 1

Step-by-step explanation:

a=7

d=12-7=5

An=a+(n-1) d

=7+(n-1) 5

=7+5n-5

=2+5n

nth term=2+5n

Answer 2

sn=7+12+20

sn=7+1220+1tn-2,tn-1,tn

0=7+{5+8+11+(tn- tn-1)}-tn

tn-7=5+8+1(tn-tn-1)

n-1/2(10+(10-8+3n)

tn=3n^2+4n-3n-4+7

TN ={3N^2+N+10}