Question

Thé nth term rule for a sequence is 4n + 7 what is the 3rd term of this sequence?

Answer 1

a₃ = 19

Explanation:

to find the third term substitute n = 3 into the nth term rule

a₃ = 4(3) + 7 = 12 + 7 = 19

Answer 2

a₃ = 19

Explanation:

the relationship between any two terms of an arithmetic sequence (in our case the relationship between the 3rd term and nth term) gives us this equality :

`a_n - a_3 = 4(n-3)`

Then

4n + 7 - a₃ = 4n - 12

Then

7 - a₃ = - 12

Then

7 + 12 = a₃

Then

a₃ = 19