MS Algebra A-F-IF-7 – Ch. 6.2Solving Word Problems by WritingEquations in Slope-Intercept Form

ALGEBRA SUPPORT

Solving Word Problems by Writing Equations in Slope-Intercept Form

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.

SUPPORT Class Learning Target

Title: 6.2 Apply Slope-Intercept Form to Solve Word Problems Date:

Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?

2) Section 6.2 Pg. 334-335 3) Section ______

TxtBk.Prob. #28,33,37-43 ALL Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?

Table of ContentsDate Description Date Due

HW # 28

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.

Error Analysis

F S

8 22

5 16

S = refrigerator space (ft3) b = starting spaceF = number of family membersm = cubic feet per family member

m = 8 – 5

22 – 16

= 36

= ½

Step 1:

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

The error I see in the calculation is

____________________________

____________________________.I would correct the error by

____________________________

____________________________.

HW # 33

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.

Error Analysis

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

The error I see in the calculation is

____________________________

____________________________.I would correct the error by

____________________________

____________________________

____________________________.

ERRORy = mx + b

C = mT + b81 = m(2) + 1863 = m(2)

31.50 = m

C = total cost b = initial set-up feeT = number of months of servicem = cost of service per month

CORRECTION

y = mx + b

Notes: How To Get To Slope-Intercept Form

Slope-Intercept Form of a Linear Equation

m = slopeb = y-intercept

Step 1) Make a table

Use the two points to calculate SLOPE (m)

x y

X1 Y1

X2 Y2

Step 2) Plug m and one point into y = mx + bSolve for b

(Y1) = m(X1) + b

Step 3) Write general formula with m and b

m = Y2 – Y1

X2 – X1

HW # 37

Four years after a tree was planted, its height was 9 feet.

Eight years after it was planted, its height was 12 feet.

BIOLOGY

Given 2 data points

Y H

H = height of tree Y = years after plantedm = growth rate b = original height of tree

m = Step 1:

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

Step 2:

General Equation:

What is the average growth rate of the tree?

What was its height when it was planted?

H = mY + b

HW # 38

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 $34.80.

After viewing 30 archived articles, you paid a total of $40.70.

Online Magazine

Given 2 data points

A C

C = total cost A = articles viewedm = cost per article b = original subscription cost

m = Step 1:

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

Step 2:

General Equation:

What is the cost per archived article after the first 25 articles viewed?

What is the cost of the magazine subscription?

HW # 39

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 19,306airports in the U.S. in 2001. Which equation gives the number of U.S.

airports as a function of the number of years since 1990?

Multiple Choice

A) y = 175x + 19,306

B) y = 175x + 17,381

C) y = 175x + 16,521

D) y = 19,306x + 175

y = mx + b

HW # 40-41

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 903Sunday newspapers in circulation.

Newspapers

Given 2 data points

m = Step 1:

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

Step 2:

General Equation:

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.

HW # 42-43

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 903Sunday newspapers in circulation.

Newspapers

Given 2 data points

m =

Step 1: Find the slope between 2 points

Step 2: Find the value of b using m and 1 point

Step 3: Write general y = mx + b equation

About how many Sunday newspapers were in circulation in 2000?

In 2004, there were 915 Sunday newspapers in circulation. Does the model predict this result? EXPLAIN by considering the function’s domain.

General Equation:

2000- 1970

30 years x The model does / does not predict the result because

_________________________

_________________________

_________________________.

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 _______________

_______________________________________________

______________________________________________

______________________________________________.

1) Slope

2) y-intercept

3) Data Pair

4) Slope-Intercept Form

5) Point-Slope Form

Vocabulary

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

Friendly DefinitionSketch

Wordwork Sentence

DAY 2

1. Review word

Friendly Definition

Physical Representation

2. Draw a sketch

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

DAY 1

1. Use Visuals

2. Introduce the word

Friendly Definition

Physical Representation

3. Use Cognates

4. Write friendly definition

5. Physical Representation

Word List1.2.3.4.

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.

SUPPORT Class Learning Target

Title: 6.2 Apply Slope-Intercept Form to Solve Word Problems Date:

Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?

2) Section 6.2 Pg. 334-335 3) Section ______

TxtBk.Prob. #28,33,37-43 ALL Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?

Table of ContentsDate Description Date Due

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

Ticket OUT.

-1 = -2(4) + b-1 = -8 + b

7 = b

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 5m = -1 - 5

4 - 1

Step 2: Find the value of b using m and 1 point

= -6

3= -2

Step 3: Write general y = mx + b equation

y = -2x + 7