Interpreting Equations
1) The table below shows my income from age 26 – 30. Use the data to answer the following questions.
Age
Income ($1000)
26
16.8
27
19.1
28
23.3
29
25.8
30
33.9
Identify the independent variable and dependent variables.
Write a sentence describing the relationship between the two variables.
Describe what the ordered pair (28, 23.3) means in the context of the data.
Use (27, 19.1) and (29, 25.8) to write a linear equation.
What does the y-intercept mean in general?
What is the y-intercept from your line? ______ What does your y-intercept mean in the context of the problem?
What does slope mean in general?
What is the slope from your line? ______ What does your slope mean in the context of the problem?
Using your equation, how much will I make when I’m 40 years old.
Using your equation, determine how old I’ll be when I make $60,000.
2. The table below shows the percent of budget the average person spends on entertainment at various ages. Use it
to answer the following questions.
Age
% of budget spent on
entertainment
30
6.1
40
6.0
50
5.4
60
5.0
70
4.7
80
3.4
Use (40, 6.0) and (60, 5.0) to write a linear equation.
What is the y-intercept from your line? ______ What does your y-intercept mean in the context of the problem?
Does your interpretation of the y-intercept make sense? Why or why not?
What is the slope from your line? ______ What does your slope mean in the context of the problem?
What % of my budget do I spend on entertainment now? (I’m 38)
3. This is a totally made up data set designed to convince you to study. Use it to answer the following questions.
Studying Time (min)
Test Score(%)
10
53
20
67
30
78
40
87
50
95
Use (20, 67) and (40, 87) to write a linear equation.
What is the y-intercept from your line? ______ What does your y-intercept mean in the context of the problem?
What is the slope from your line? ______ What does your slope mean in the context of the problem?
Interpreting Equations Worksheet
1. Given y = .5125x + 4.5 where x is the years since 1980 and y is federal spending on
space in billions of dollars:

Interpret the y-intercept in context.

Interpret the slope in context.
2. Given y = -1200x + 12000, where x is the age of the car in years and y is the cost of
the car in dollars:

Interpret the y-intercept in context.

Interpret the slope in context.
3. Given y = 2000x + 2500, where x is the number of years since I opened a savings
account and y is the amount of money in the account in dollars.

Interpret the y-intercept in context.

Interpret the slope in context.
4. Given y = 2.6x + 41.6, where x the length of a whale in feet and y is the weight of the
whale in tons.

Interpret the y-intercept in context.

Interpret the slope in context.