Algebra 2 question- logarithms

Question

Car depreciation- The value of a new car purchased for $20,000 decreases by 10% per year. Write an exponential decay model for the value of the car. Use the model to estimate the value after one year.

Answer 1

Y= 20000 x .9^x. If the value decreases by 10% it is only worth 90% or .9 of its value

y=20000 x .9^1

y= 20000 x .9

y= 18000