(i) 3, 1, – 1, – 3 …

(ii) -5, – 1, 3, 7 …

Solution(i):

3, 1, – 1, – 3 …

The first term is, a = 3

And, the Common difference, d = Second term – First term

Therefore,

⇒  1 – 3 = -2

⇒  d = -2

Solution(ii):

The first term is, a = -5

And the Common difference, d = Second term – First term

Therefore,

⇒ ( – 1)-( – 5) = – 1+5 = 4