Which is an equation for the nth term of the sequence? 12, 15, 18, 21, question 1 options: a) = 12n + 3 b) = 3n + 9 c) = n + 3 d) = 9n + 3

 The correct option is (B)

Step-by-step explanation:  We are given to select the equation that represents the nth term of the following sequence :

12,   15,   18,   21,  .    .   .

We see that

the given sequence is an arithmetic one with first term a = 12  and common difference d given by

d = 15 - 12 = 18 - 15 = 21 - 18 =  .   .   .   =3.

We know that

the nth term of an arithmetic sequence with first term a and common difference d is given by

Therefore, the nth term of the given sequence is

Thus, the required nth term of the given sequence is

Option (B) is CORRECT.