Question

the 7th tetm of an AP is -4 and its 13th term is -16 . find the AP

Answer 1

a7=-4
a13=-16


a7=a+6d
-4=a+6d.........1 eq

a13=a+12d
-16=a+12d...... 2eq


By elimination method..
we get


d=2

put d in eq 1
a7=a+6d
-4=a+6*2
-4=a+12
-4-12=a
a=-16

hence

Ap = - 16,-14,-12......