Answer:
aₙ=5*4ⁿ⁻¹
Explanation:
The common ratio is r=80/20=20/5=4
The explicit formula for a geometric sequence is aₙ=a₁*rⁿ⁻¹ where aₙ is the nth term, r is the common ratio, and a₁ is the first term.
Given:
a₁=5
r=4
Therefore, the explicit formula for the sequence is aₙ=5*4ⁿ⁻¹