Find the next three terms in the sequence 3, 12, 21

Solution:

The series 3, 12, 21 is in an arithmetic sequence with the first term a = 3 and the common difference d = 9.

The n^th term will be equal to :

T_n = a + (n -1)d

= 3 + (n - 1)9

Therefore the next three terms are

T₍₄₎ = 3 + (4 - 1)(9) = 3 + 27 = 30

T₍₅₎ = 3 + (5 - 1)(9) = 3 + 36 = 39

T₍₆₎ = 3 + (6 - 1)(9) = 3 + 45 = 48

Find the next three terms in the sequence 3, 12, 21

Summary:

The next three terms in the sequence 3, 12, 21 are 30, 39 and 45