Given a₂ = 15 and a₅ = –3,240 of a geometric sequence, what is the recursive equation for the nth term?
a. aₙ = 6(aₙ₋₁), a₁ = –2.5
b. aₙ = 6(aₙ₋₁), a₁ = 2.5
c. aₙ = –6(aₙ₋₁), a₁ = –2.5
d. aₙ = –6(aₙ₋₁), a₁ = 2.5