Answer:
a₄₂ = 107
Step-by-step explanation:
The nth term of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Given a₂₇ = 66 , then
a₁ + 26d = 66 , that is
- 12 + 26d = 66 ( add 12 to both sides )
26d = 78 ( divide both sides by 26 )
d = 3
Then
a₄₂ = - 16 + (41 × 3) = - 12 + 123 = 111
