GRAPHING EQUATIONS Use a table of values to graph the equation.
40. y 3x 3
41. y 4x 2
42. y 3x 4
43. y 5x 2
44. x y 1
45. 2x y 3
46. y 4x 1
47. x 4y 48
48. 5x 5y 25
TRAINING FOR A TRIATHLON In Exercises 49–51, Mary Gordon is training
for a triathlon. Like most triathletes she regularly trains in two of the
three events every day. On Saturday she expects to burn about 800
calories during her workout by running and swimming.
Sports
Running:
7.1 calories per minute
10.1 calories per minute
Swimming:
Bicycling:
6.2 calories per minute
49. Copy and complete the model below. Let x represent the number of minutes
she spends running, and let y represent the number of minutes she spends
swimming.
TRIATHLON A triathlon is a
VERBAL
MODEL
Calories burned p
Swimming Total calories
? ? p
while running
time
burned
LABELS
Calories burned while running ?
INT
race that has three parts:
running, swimming, and
bicycling.
NE
ER T
More about triathlons
is available at
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(calories/minute)
Running time x
(minutes)
? 10.1
(calories/minute)
? y
(minutes)
Total calories burned 800
ALGEBRAIC
MODEL
? p x ? p y 800
(calories)
Write a linear model.
50. Make a table of values and sketch the graph of the equation from
Exercise 49.
51. If Mary Gordon spends 45 minutes running, about how many minutes will
she have to spend swimming to burn 800 calories?
In Exercises 52 and 53, use the table showing the boiling
point of water (in degrees Fahrenheit) for various altitudes (in feet).
Altitude
Boiling Point
0
500
1000
1500
2000
2500
212.0
211.1
210.2
209.3
208.5
207.6
52. Make a graph that shows the boiling point of water and the altitude. Use the
horizontal axis to represent the altitude.
53. INTERPRETING DATA Describe the relationship between the altitude and
the boiling point of water.
214
Chapter 4
Graphing Linear Equations and Functions