Question

S7 of an AP=49, S17 of an AP =289, find S10

Answer 1

Answer:

f7 = 49

f17 = 289

d = 289-49

17 - 7

= 240

10

= 24

f1 = 49 - 6*24

= -95

Sn = 10[2*-95+(10-1)*2]

2

= 5* -190 + 216

= 5*26

= 130

I think so like this.. Thank you for choosing my answers..