C Challenge

22. 1. Make a scatter plot of the data below. Then find the equation of the line of best fit. Draw the line of best fit on your scatter plot.

       Car Stopping Distances

       Speed (mi/h)	10	15	20	25	30	35	40	45
       Stopping Distance (ft)	27	44	63	85	109	136	164	196

    2. Use your equation to predict the stopping distance at 90 mi/h.
    3. Reasoning The actual stopping distance at 90 mi/h is close to 584 ft. Why do you think this distance is not close to your prediction?
    4. Suppose you plot (90, 584) on your scatter plot. What effect would it have on the slope and y-intercept of the line of best fit you found in part (a)?

Standardized Test Prep

SAT/ACT

23. Suppose you survey each school in your state. What relationship would you expect between the number of students and the number of teachers in each school?

    1. positive correlation
    2. negative correlation
    3. no correlation
    4. none of the above

24. A horizontal line passes through ( 5 , − 2 ) . open 5 comma negative 2 close .  Which other point is also on the line?

    6. (5, 2)
    7. ( − 5 , − 2 ) open negative 5 comma negative 2 close
    8. ( − 5 , 2 ) open negative 5 comma 2 close
    9. (5, 0)

25. When 18 gal of water are pumped into an empty tank, the tank is filled to three fourths of its capacity. How many gallons of water does the tank hold?

    1. 12
    2. 13.5
    3. 18.5
    4. 24

Short Response

26. The table shows the balance of a student's bank account at various times. Estimate how much money is in the student's bank account in Week 6. Justify your answer.

    Weekly Account Balance

    Week	1	3	4	7	9
    Account Balance	$35	$68	$85	$105	$136

Mixed Review

See Lesson 5-6.

Write an equation of the line in slope-intercept form that passes through the given point and is parallel to the graph of the given equation.

27. y = 5 x + 1 ; ( 2 , − 3 ) y equals 5 x plus 1 semicolon open 2 comma negative 3 close
28. y = − x − 9 ; ( 0 , 5 ) y equals negative x minus 9 semicolon open 0 comma 5 close
29. 2 x + 3 y = 9 ; ( − 1 , 4 ) 2 x plus 3 y equals 9 semicolon open negative 1 comma 4 close

Get Ready! To prepare for Lesson 5-8, do Exercises 30–33.

See Lesson 1-5.

Find each absolute value.

30. | 2 − 7 | absolute value of 2 minus 7 , end absolute value ,
31. | 7 − 7 | absolute value of 7 minus 7 , end absolute value ,
32. | 56 − 38 | absolute value of 56 minus 38 , end absolute value ,
33. | − 24 + 12 | absolute value of negative 24 plus 12 , end absolute value ,

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