Modeling with Linear Functions

An office machine purchased new for $3600 loses $400 each year.

Assume the value continues to decrease the same amount each year. If f(x) represents the value of the office machine after x years, which linear function models the given situation?

A f(x) = 400x + 3600f(x) = 400x + 3600
B f(x) = −400x − 3600f(x) = −400x − 3600
C f(x) = −400x + 3600f(x) = −400x + 3600
D f(x) = 400x − 3600

How many years will it take for the office machine's value to equal zero?
Responses
A 55
B 66
C 99
D 12

The linear function that models the given situation is C) f(x) = -400x + 3600. This is because the machine loses $400 each year, which translates to a negative slope of -400 in the linear function.

To find out how many years it will take for the office machine's value to equal zero, we can set f(x) = 0 and solve for x:

0 = -400x + 3600
400x = 3600
x = 9

Therefore, it will take 9 years for the office machine's value to equal zero.