Question

The Зrd tеrm
of an
AP is a-2b & 5th
term is a+5b
find first term​

Answer 1

Solution:

t3 = a - 2b ... (1)

t5 = a + 5b ... (2)

A = ?

t5 - t3 = 2d

» 2d = 7b

» d = 7b/2

Substitute in (1), we get

a - 2b = A + 2d

=> a - 2b = A + 7b

=> A = a - 9b

The first term is a - 9b.