Question

The nth term of a linear sequence is 3n+c. the fourth term is 17

a. Work out the value of c
b. What is the first term of the sequence

Answer 1

(a) c = 5 , (b) first term = 8

Explanation:

(a)

given the nth term is 3n + c

where n is the term number

given the fourth term is 17, that is n = 4

equate 3n + c = 17

substitute n = 4

3(4) + c = 17

12 + c = 17 ( subtract 12 from both sides )

c = 5

then nth term is 3n + 5

(b)

substitute n = 1 to find the first term

first term = 3(1) + 5 = 3 + 5 = 8