Lesson 7: Practice Problems

Problem 1

The equation and the tables represent two different functions. Use the equation and the table to answer the questions. This table represents as a function of .

  1. When is -3, is or greater?

  2. When is 21, what is the value of ? What is the value of that goes with this value of ?

  3. When is 6, is or greater?

  4. For what values of do we know that is greater than ?

Problem 2

Elena and Lin are training for a race. Elena runs her mile at a constant speed of 7.5 miles per hour.

Lin’s total distances are recorded every minute:

time (minutes)

distance (miles)

  1. Who finished their mile first?

  2. This is a graph of Lin’s progress. Draw a graph to represent Elena’s mile on the same axes.

    A scatterplot in a coordinate plane with the origin labeled “O.” The horizontal axis is labeled “time in minutes” and the numbers 1 through 12 are indicated. The vertical axis is labeled “distance in miles,” and the number 1 is indicated. The graph shows the trend of the data points moving approximately linearly upward and to the right. The coordinates of the points are as follows: 1 comma 0 point 11, 2 comma 0 point 2 1, 3 comma 0 point 3 2, 4 comma 0 point 4 1, 5 comma 0 point 5 3, 6 comma 0 point 6 2, 7 comma 0 point 7 3, 8 comma 0 point 8 5, 9 comma 1.

  3. For these models, is distance a function of time? Is time a function of distance? Explain how you know.

Problem 3 From Unit 5 Lesson 2

Match each function rule with the value that could not be a possible input for that function.

  1. 3 divided by the input

  2. Add 4 to the input, then divide this value into 3

  3. Subtract 3 from the input, then divide this value into 1

  1. 3

  2. 4

  3. -4

  4. 0

  5. 1

Problem 4 From Unit 4 Lesson 4

Find a value of that makes the equation true. Explain your reasoning, and check that your answer is correct.