Finding the function

Question

A new television depreciates $120 per year, and it is worth $340 after 4 years, find the function that describes the value of this television, if x is the age of the television in years

Answer 1

The rate in which the television depreciates is the slope of the line, and the y-intercept represents the value of the television brand new.

 

Let y = the value of the television 

 

The given point in which the equation of the line goes through (4,$340) Hence, the initial equation can be written as

 

y-340=-120(x-4)=-120x+480

 +340                          +340

 

y=-120x+820