A writer buys a new laptop for $1866. Every year the laptop decreases in value by 20% Which exponential function can be used to find the value of the laptop after u years?
a. A(u) = 1866(1.8)ᵘ
b. A(u) = 1866(0.8)ᵘ
c. A(u) = 1866(0.2)ᵘ
d. A(u) = 1866(1.2)ᵘ