Question

Ok Sofia I could get some help on this, it would be awesome :)

Answer 1

$a_{n}$ = a₁ + d(n - 1)

In the given problem, a₁ = 15 and d = 3

$a_{n}$ = 15 + 3(n - 1)  = 15 + 3n - 3   = 3n + 12

$a_{56}$ = 3(56) + 12  = 168 + 12   = 180

Answer: $a_{n}$ = 3n + 12, 180