Question

Find the first four terms in the sequence

an 15 + 6n

A. 21, 27, 33, 39
B. 18, 12, 6,0
C. 20, 26, 32, 38
D. 20, 14, 8, 2

Answer 1

A

Explanation:

You do not know where n starts. Is it 1 or zero or something else. Raise your hand and complain.

I'll assume that n = 1 to start with

n = 1

15 + 6(1) = 21

n = 2

15 + 6(2) = 15 + 12 = 27

n = 3

15 + 6* 3 = 33

n = 4

15 + 6*4 = 39

Answer 2

A. 21, 27, 33, 39

Explanation:

an =15 + 6n

Let n=1

a1 = 15 +6(1) = 15+6 = 21

Let n=2

a2 = 15 +6(2) = 15+12 = 27

Let n=3

a3 = 15 +6(3) = 15+18 = 33

Let n=4

a4 = 15 +6(4) = 15+24 = 39