Answer:
a₁ = 36
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 the sequence has 12 terms and the last term is 80 , then
a₁₂ = 80 , that is
a₁ + (11 × 4) = 80
a₁ + 44 = 80 ( subtract 44 from both sides )
a₁ = 36