MATH 1101 Math Modeling Section 3.2 notes
The formula for a linear function is
y = ________________(x) +__________________________
or y = ________________(x) +__________________________
Example 1
A long distance company charges its customers $5 a month and 7 cents per minute used for a certain long distance
plan.
a) Write a linear function for the long distance plan. Define your input and output variables.
b) What is the slope? (include units) ______________________ Interpret the slope in practical terms.
c) Explain the initial value or y-int in practical terms.
d) Graph the equation for up to 300 long distance minutes used.
Example 2
Suppose that you bought a car in 2002 for $18,000. On average, the car’s value decreases at a rate of $2800 per
year.
a) Write a linear equation that models this situation. Define your input and output variables.
b) If you let the input variable be defined as x = the year, what would be your y-int?
c) Graph the above equation. Over what years do you think the equation is good for?
