Question

IF 21 , a , b , -3 are in ap then find the value of a+b

Answer 1

a-21=d     eqn1  where d is the common difference of AP 
b-a=d eqn2 
-3-b=d eqn3
RHS OF EQN 1 and 3 are same so a-21=-3-b so a+b=-3+21=18

Hope this helps you!

Answer 2

Answer:

Step-by-step explanation:

a-21=d

eqn1 where d is the common difference of AP

b-a=d eqn2

-3-b=d eqn3

RHS OF EQN 1 and 3 are same so a-21=-3-b so a+b=-3+21=18

Hope it helps..!!

Good luck