F(n)=45⋅(4/5)^n−1
complete the recursive formula of f(n)

F(1) = 45

f(n) = f(n-1) * 4/5

Step-by-step explanation:

f(n) = 45 x (4/5)ⁿ⁻¹

f(1) = 45 x (4/5)¹⁻¹ = 45 x (4/5)⁰ = 45 x 1 = 45

f (n-1) = 45 x (4/5)ⁿ⁻¹⁻¹ = 45 x (4/5)ⁿ⁻²

f(n) = f(n-1) * (4/5)¹ = 45 x (4/5) ⁿ⁻²⁺¹ = 45 x (4/5)ⁿ⁻¹

e.

step-by-step explanation:

because there are always 10 numbers in a phone number.