help please. i really need to pass

Answer:
Number of year, when final value is $61,412.50 = 3 year
Number of year, when final value is $20,000 = 10 year (Approx.)
Step-by-step explanation:
Given:
Depreciation model
y = 100,000[0.85]ˣ
Where x = Number of year
Find:
Number of year, when final value is $61,412.50
Number of year, when final value is $20,000
Computation:
Depreciation model
y = 100,000[0.85]ˣ
61,412.50 = 100,000[0.85]ˣ
0.614125 = [0.85]ˣ
x = 3
Number of year, when final value is $61,412.50 = 3 year
Depreciation model
y = 100,000[0.85]ˣ
20,000 = 100,000[0.85]ˣ
0.2 = [0.85]ˣ
x = 10 (Approx.)
Number of year, when final value is $20,000 = 10 year (Approx.)