1. Solving Word Problems by Writing Equations in Slope-Intercept Form
MS Algebra A-F-IF-7 – Ch. 6.2 Solving Word Problems by Writing Equations in Slope-Intercept Form
ALGEBRA SUPPORT
Solving Word Problems by Writing Equations in Slope-Intercept Form

2. SUPPORT Class Learning Target
Title: 6.2 Apply Slope-Intercept Form to Solve Word Problems
Date:
SUPPORT Class Learning Target
By the end of the period, I will apply the slope formula and the slope-intercept form to write equations and solve word problems.
I will demonstrate this by completing Four-Square Notes and by solving problems in a pair/group activity.

3. Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?
2) Section 6.2 Pg ) Section ______
TxtBk.Prob. #28,33,37-43 ALL Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?
Table of Contents
Date Description Date Due

4. Step 1: Find the slope between 2 points
HW # 28
Error Analysis
Step 2: Find the value of b using m and 1 point
Step 3: Write general y = mx + b equation
An appliance store uses a rule of thumb to determine how much refrigerator space (in cubic feet) a family will need. A salesperson suggests that a family of 5 buy a refrigerator with 16 cubic feet of space and that a family of 8 buy a refrigerator with 22 cubic feet of space. Describe and correct the error in finding the amount of refrigerator space per family member.
The error I see in the calculation is
____________________________
____________________________.
I would correct the error by
8 – 5
Step 1:
m =
22 – 16 F S 8 22 5 16 3 6 = =
S = refrigerator space (ft3) b = starting space
F = number of family members
m = cubic feet per family member 4

5. Step 1: Find the slope between 2 points
HW # 33
Error Analysis
Step 2: Find the value of b using m and 1 point
Step 3: Write general y = mx + b equation
An internet service provider charges $18 per month plus an initial set-up fee. On customer paid a total of $81 after 2 months of service. Describe and correct the error in finding the set-up fee.
CORRECTION
ERROR
y = mx + b
C = mT + b
81 = m(2) + 18
63 = m(2)
31.50 = m
The error I see in the calculation is
____________________________
____________________________.
I would correct the error by
C = total cost b = initial set-up fee
T = number of months of service
m = cost of service per month 5

6. Slope-Intercept Form of a Linear Equation
How To Get To Slope-Intercept Form
Notes:
Given
Two
Points x y X1 Y1 X2 Y2
Step 1) Make a table
Use the two points to calculate SLOPE (m)
Y2 – Y1
m =
X2 – X1
Step 2) Plug m and one point into y = mx + b
Solve for b
(Y1) = m(X1) + b
Step 3) Write general formula with m and b
y = mx + b
m = slope
b = y-intercept
Slope-Intercept Form of a Linear Equation

7. Step 1: Find the slope between 2 points
HW # 37
BIOLOGY
Step 2: Find the value of b using m and 1 point
Given 2 data points
Step 3: Write general y = mx + b equation
Four years after a tree was planted, its height was 9 feet. Eight years after it was planted, its height was 12 feet.
What is the average growth rate of the tree?
What was its height when it was planted?
Step 1:
Step 2:
m = Y H
H = mY + b
General Equation:
H = height of tree Y = years after planted
m = growth rate b = original height of tree 7

8. Step 1: Find the slope between 2 points
HW # 38
Online Magazine
Step 2: Find the value of b using m and 1 point
Given 2 data points
Step 3: Write general y = mx + b equation
You have a subscription to an online magazine that allows you to view 25 articles from the magazine’s archives. You are charged an additional fee for each article after the first 25 articles viewed. After viewing 28 archived articles, you paid a total of $ After viewing 30 archived articles, you paid a total of $40.70.
What is the cost per archived article after the first 25 articles viewed?
What is the cost of the magazine subscription?
Step 2:
Step 1:
m = A C
General Equation:
C = total cost A = articles viewed
m = cost per article b = original subscription cost 8

9. HW # 39
y = mx + b
Multiple Choice
From 1990 to 2001, the number of airports in the U.S. increased at a relatively constant rate of 175 airports per year. There were 19,306 airports in the U.S. in Which equation gives the number of U.S. airports as a function of the number of years since 1990?
A) y = 175x + 19,306
B) y = 175x + 17,381
C) y = 175x + 16,521
D) y = 19,306x + 175 9

10. Step 1: Find the slope between 2 points
HW # 40-41
Newspapers
Step 2: Find the value of b using m and 1 point
Given 2 data points
Step 3: Write general y = mx + b equation
From 1970 to 2000, the number of Sunday newspapers in circulation increased at a relatively constant rate of 11.8 newspapers per year. In 1997 there were 903 Sunday newspapers in circulation.
About how many Sunday newspapers were in circulation in 1970? (what is b?)
Write an equation that gives the number of Sunday newspapers in circulation as a function of the number of years since 1970.
Step 1:
m =
General Equation:
Step 2: 10

11. Step 1: Find the slope between 2 points
HW # 42-43
Newspapers
Step 2: Find the value of b using m and 1 point
Given 2 data points
Step 3: Write general y = mx + b equation
From 1970 to 2000, the number of Sunday newspapers in circulation increased at a relatively constant rate of 11.8 newspapers per year. In 1997 there were 903 Sunday newspapers in circulation.
In 2004, there were 915 Sunday newspapers in circulation. Does the model predict this result? EXPLAIN by considering the function’s domain.
About how many Sunday newspapers were in circulation in 2000?
2000
- 1970
30 years  x
m =
The model does / does not predict the result because
_________________________
_________________________.
General Equation: 11

12. Storm Check (Think, Write, Discuss, Report)
If you are given two points, how can you create a linear equation that is in slope-intercept form?
(2-3 sentences)
When given two points, I can create a linear
equation in slope-intercept form by _______________
_______________________________________________
______________________________________________
______________________________________________.

13. Vocabulary Slope y-intercept Data Pair Slope-Intercept Form
Point-Slope Form

14. Vocabulary Acquisition
Friendly Definition
Sketch
Wordwork
Sentence
DAY 2
1. Review word
Friendly Definition
Physical Representation
2. Draw a sketch
DAY 1
Use Visuals
Introduce the word
Friendly Definition
Physical Representation
Use Cognates
Write friendly definition
Word List
Vocabulary Acquisition
DAY 3 and/or DAY 4
1. Review the word
Friendly Definition
Physical Representation
2. Show how the word works
Synonyms/antonym
Word Problems
Related words/phrases
Example/non-example
DAY 5
1. Review the word
Friendly definition
Physical Representation
3. Write a sentence
at least 2 rich words (1 action)
correct spelling
correct punctuation
correct subject/predicate agreement
clear and clean writing

15. SUPPORT Class Learning Target
Title: 6.2 Apply Slope-Intercept Form to Solve Word Problems
Date:
SUPPORT Class Learning Target
By the end of the period, I will apply the slope formula and the slope-intercept form to write equations and solve word problems.
I will demonstrate this by completing Four-Square Notes and by solving problems in a pair/group activity.

16. Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?
2) Section 6.2 Pg ) Section ______
TxtBk.Prob. #28,33,37-43 ALL Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?
Table of Contents
Date Description Date Due

17. Ticket OUT.
Write an equation of the line that passes through the points (1, 5) and (4, –1).
Step 1: Find the slope between 2 points x y
Step 2: Find the value of b using
m and 1 point
Step 3: Write general y = mx + b equation
Turn to your partner and share your answer. Please use correct answer.
Partner B, please share what Partner A told you.

18. y = -2x + 7 -2 m = = = -1 = -2(4) + b -1 = -8 + b 7 = b -1 - 5 -6
Ticket OUT.
Write an equation of the line that passes through the points (1, 5) and (4, –1).
Step 1: Find the slope between 2 points x y 4 -1 1 5
-1 - 5 -6 -2
m = = =
4 - 1 3
Step 2: Find the value of b using
m and 1 point
Step 3: Write general y = mx + b equation
Turn to your partner and share your answer. Please use correct answer.
Partner B, please share what Partner A told you.
y = -2x + 7
-1 = -2(4) + b
-1 = -8 + b
7 = b