(Q25).In an AP:
(vii) Given l = 28, S = 144, and there are total 9 terms. Find a.
Given:
l = a
9
= a +
d = 28 and S
9
=
But,
Now, S
n
=
n
2
(a+l)
=
2
(a+
)
⇒
×
= a +
⇒ a +
=
⇒ a =
Clear