Question

the value of s car depreciates by 20% at the beginning of each year. if the car costs 1 million find the value of the car after 2 years.

Answer 1

depreciation is usually linear, so 100% - 2*20% = 60%
60% of 1,000,000 = 600,000

If you want to use a more complicated exponential model, then
1,000,000 * 0.80^2 = 640,000