Answer:
1. [tex]f(x) = 750\cdot 0.72^{x}[/tex]
Step-by-step explanation:
The cell phone experiments an exponential depreciation, which is defined by the following formula:
[tex]f(x) = C_{o}\cdot (1-r)^{x}[/tex], for [tex]0<r< 1[/tex]. (1)
Where:
[tex]C_{o}[/tex] - Initial cost, measured in monetary units.
[tex]r[/tex] - Depreciation rate, no unit.
[tex]x[/tex] - Time, measured in years.
[tex]f(x)[/tex] - Current value of the cell phone, measured in monetary units.
If we know that [tex]C_{o} = \$\,750[/tex] and [tex]r = 0.28[/tex], then the exponential decay function that represents the situation is:
[tex]f(x) = 750\cdot 0.72^{x}[/tex]
Which means that correct answer is 1.
