Answer:
see explanation
Step-by-step explanation:
Note the common difference d between consecutive terms
d = 10 - 3 = 17 - 10 = 24 - 17 = 7
This means the sequence is arithmetic with n th term
[tex]a_{n}[/tex] = a₁ + (n - 1)d
Here a₁ = 3 and d = 7, thus explicit formula is
[tex]a_{n}[/tex] = 3 + 7(n - 1) = 3 + 7n - 7 = 7n - 4, thus
[tex]a_{18}[/tex] = (7 × 18) - 4 = 126 - 4 = 122
