Which of the following are APs? If they form an AP, find the common difference d and write three more terms.

-1.2, -3.2, -5.2, -7.2, . . .

For a series to be in AP, the common difference (d) should be

Equal.

D₁ = second term – first term = -3.2 – (-1.2) = -2

D₂ = Third term - Second term = -5.2 – (-3.2) = -2

Since common difference is equal the above series is in AP

The next three terms will be the 5^th, 6^th, 7^th.

5^th term will be given by

= a + (5-1)d = a + 4d = -1.2 + 4(-2) = -9.2

6^th term is a + (6-1)d = a + 5d = -1.2 + 5(-2) = -11.2

7^th term is a + (7-1)d = a + 6d = -1.2 + 6(-2) = -13.2