Question

Given a=8,an=62,Sn=210,find n and d

Answer 1

..................find n and s

Step-by-step explanation:

= an=62  ........  a=8    &       = sn=210  ......... n=7.75

= 8n=62                               = 7.75s=210

= n=62/8                              =  s=210/7.75

= n=7.75                               = s=27.09

        hope it helps mark as brilliant.

     

Answer 2

Answer:

sn=n/2(2a+(n-1)d)

210=n/2(2*8+(n-1)d)

420=n(16+(n-1)d)= (equation (1))

by the formula

an=a+(n-1)d

62=8+(n-1)d

54=(n-1)d = (equation (2))

putting the value of (n-1)d in equation( 1)

Step-by-step explanation:

420=n(16+54)

420=n(70)

n=420/70

n=6

putting the value of n in equation( 2)

54=(6-1)d

54=5d

d=54/5