Name_________________
Level of Understanding
_____
7ACC Linear Functions
Summative Assessment Part 2
 I can determine the y-intercept of a function from a table, graph, equation,
or real world scenario.
 I can identify the slope and y-intercept of a real world situation and explain
their meanings.
 I can write an equation for a linear function that models a given real world
situation.
1. The Squeaky Clean Car Wash charges by the minute. This table shows the charges for
several different times.
Squeaky Clean Car Wash Charges
Time (min)
Charge
5
$8
10
$13
15
$18
20
$23
25
$28
a. Write a function to model the relationship.
b. Define the variables.
c.
What does the rate of change mean in terms of the context of the problem?
d. What does the y-intercept mean in terms of the context of the problem?
Mayfield City School District 8th Grade Math PLC
2012-13
2.
Suppose Greyhound Bus charges a $125 transportation fee plus $8.50 per passenger.
a. Write a linear equation to represent this situation.
b. What does the y-intercept represent in the context of this problem?
c. What does the slope represent in the context of this problem?
3. Write an equation to represent the graphs below.
Mayfield City School District 8th Grade Math PLC
2012-13
4. Below are 2 receipts from Squeaky Clean Car Wash. Assume the relationship between charge c
and time used m is linear. The goal is to determine the cost per minute and the flat fee cost.
Date: 1-10-13
Start Time: 2:00 pm
Each receipt represents a point (m,c) on the line.
Write an equation relating c and m.
(Level 4)
Stop Time: 2:12 pm
Charge: $8.00
Date: 2-4-13
Start Time: 2:45 pm
Stop Time: 3:01 pm
Charge: $11.00
Mayfield City School District 8th Grade Math PLC
2012-13
 I can explain how changing the slope affects the graph of a linear function.
 I can explain how changing the y-intercept affects the graph of a linear
function.
5. Suppose you have the graph of y  3 x  8 . How would the graph of y  3 x  2 compare to
y  3x  8 ?
6. Suppose you have the graph of y  4 x  5 . How would the graph of y  2 x  5 compare to
y  4 x  5 ?
2
x  2 up 5 units.
3
_____________
8. Give an equation of a line that makes y  5 x  4 twice as steep.
_____________
7. Give an equation of a line that translates y 
9. Mrs. Golem and Mr. Grano are playing a math game similar to Battleship. Mrs. Golem
starts by secretly graphing an equation. Mr. Grano tries to guess her equation. She
responds, “Booooo! The graph of your equation is 4 units below mine, and the slope is
¾ of mine.” Give a possible equation for Mrs. Golem’s graph and a possible equation for
Mr. Grano’s graph. (Level 4)
Mayfield City School District 8th Grade Math PLC
2012-13