Question

Find the sum of the following A.P.s:
(i) 2, 7, 12, ... to 12 terms​

Answer 1

Answer:

In the APa=2 d=5

Tn =a+(n-1)d

Tn=2+(12-1)5

=2+55

T 12=57

Answer 2

a=2 , d=7-2=5. Sum = n/2[2a+(n-1)d]
=12/2[2.2+(12-1)5]
=6[4+55]
=6[59]
=354