1. 4-1 Slope Intercept Form Word Problems
Goals:
Graph and interpret equations in slope-intercept form that model real life situations.
Use a graphing calculator to graph linear equations.
Eligible Content:
A / A / A / A A / A / A

2. Vocabulary
Slope is rate of change
y-intercept is the beginning amount

3. Example #1
The graph shows the number of cookies left on a plate after time has passed at a party.
Find the slope and tell what it reveals about the situation.
Find the y-intercept and tell what it reveals about the situation.

4. Example #2
The equation h = ½ t + 24 models changing river heights. h represents the height of the river (in feet) and t represents the time (in hours) since the flooding began.
What does the slope of the equation reveal about this situation?
What does the y-intercept of the equation reveal about this situation?

5. Example #3
The equation s = 15t + 25 models changing speeds of a car as it enters an expressway. s represents the speed of the car (in miles per hour) and t represents the time (in minutes).
What does the slope of the equation reveal about this situation?
What does the y-intercept of the equation reveal about this situation?

6. Using the calculator Equations must be in slope intercept form.
Press Y= button
Type in equation
Press GRAPH button
To change the x and y axes press WINDOW

7. Examples Graph each equation on your calculator: y = 3x + 4
2x + y = 8
3x – 2y = 10

8. Examples from earlier
Graph each of the word problems from earlier in class:
River: y = ½ x + 24
Car: y = 15x + 25

9. Homework
None 