Question

Write an explicit formula for an, the nth term of the sequence 15, 7,-1,...​

Answer 1

aₙ = a₁ - 8 x (n-1)

Explanation:

a₁ = 15

a₂ = 7 = a₁ - 8 x 1

a₃ = -1 = a₁ - 8 x 2

........

aₙ = a₁ - 8 x (n-1)