Answer:
a₂ = - 28.5
Step-by-step explanation:
the nth term of an arithmetic sequence is
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
here a₁ = - 45 and given a₃ = - 12 , then
a₁ + 2d = - 12 , that is
- 45 + 2d = - 12 ( add 45 to both sides )
2d = 33 ( divide both sides by 2 )
d = 16.5
Then
a₂ = a₁ + d = - 45 + 16.5 = - 28.5
