math
posted by Jane .
The value of a $20,000 car decreases every year, t. the equation below models this sitution: 20000(1  0.04t) = 13,000.
Please explain how to work this problem.

Multiply each term within the parenthesis by 20000 and solve for t:
20000  20000*0.04t = 13000.
800t = 13000  20000.
800t = 7000.
Divide both sides by 800:
t = 7000 / 800 = 8.8 Years.