Unit 2 Lesson 8: Real World Problems
Unit 2 Lesson 8:
Real World Problems
Objectives:
* I can identify the key features of the graph of a linear
function in a real world problem.
*I can interpret the key features of the graph of a linear
function in a real world problem.
Unit 2 Lesson 8: Real World Problems
Warm Up: Write a linear equation for each example and solve.
A babysitter charges a $10 fee for each job plus $8.50 per hour
of babysitting. How many hours does she need to work in order to
buy a new jacket that costs $95 with tax?
Are there any constraints on the variables?
Unit 2 Lesson 8: Real World Problems
Warm Up: Write a linear equation for each example and solve.
Brad is riding his bike at a constant speed from his house to
school. He can ride 12 miles per hour. How long will it take him to
get to school if the trip is 6 miles?
Are there any constraints on the variables?
Unit 2 Lesson 8: Real World Problems
Constraints and Key Features
In this lesson, we will identify and interpret the key features of
functions to help us describe constraints in more detail.
A piano is being lowered from an apartment that is 18 feet above the sidewalk. The piano
descends at a constant rate. The piano's elevation over time is represented by the linear
function graphed in your notes. Identify and interpret the key features of the graph.
Domain
x-intercept
Range
y-intercept
Intervals of increase/decrease
Unit 2 Lesson 8: Real World Problems
You try...
A cylinder contains 20 millimeters of water. The water begins to
leak out as represented by the linear function graphed below.
Identify and interpret the key features of the graph.
Domain
x-intercept
Range
y-intercept
Intervals of increase/decrease
Unit 2 Lesson 8: Real World Problems
Let's try another one...
The cost of a taxi ride includes a $3 fee plus $2 for each mile traveled. Write
an equation for this situation and graph the linear function. Identify and
interpret the key features of the linear function you created.
Unit 2 Lesson 8: Real World Problems
Your turn...
Snow fell for 9 hours at a rate of 1/2 inch per hour. Before the storm began, there were
6 inches of snow on the ground. Write a linear equation for this situation and graph the
linear function. Identify and interpret the key features of the function you created.
Unit 2 Lesson 8: Real World Problems
A taxicab charges $1.25 per mile plus a flat fee of $5 per ride.
Write and graph an equation for this situation.
How many miles would you have traveled if your total cost were
$57.50?
Unit 2 Lesson 8: Real World Problems
Let's review some key words to help us setup equations from
word problems...
Unit 2 Lesson 8: Real World Problems