UNIT 2: Algebraic Expressions and Equations

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UNIT 2: Algebraic

Expressions and

Equations

Algebra I 2011-2012

Lesson # 1 – 1: Using Variables

Define and give an example of the following

Variable:______________________________________

Expression: ____________________________________

Equation:______________________________________

Key words for writing expressions:

Addition Subtraction Multiplication Division

Certain terms are clues that we need to switch the order that the terms are given to us in a word problem. We call these terms _______________. Star (*) the switches listed above

Example 1: Writing an Algebraic Expression

Write an algebraic expression for each phrase. a. Seven more than a number ‘n’ __________ b. The difference of a number

, ‘n’, and seven

__________ c. The product of seven and a number, ‘n’ d.

The quotient of a number,’n’, and seven e. The quotient of 4.2 and a number, ‘c’ f. A number,’t’, minus 15

__________

__________

__________

__________ g. *five less than a number, x h. *Twelve subtracted from a number, b

__________

__________ i. *A number, n, added to ten __________

Example 2: Writing an Algebraic Expression

Define a variable and write an algebraic expression for each phrase. a. Two times a number plus five

Define the variable: _____________________

Write the expression: _____________________ b. Seven less than three times a number

Define the variable: _____________________

Write the expression: _____________________ c. Nine less than a number

Define the variable: _____________________

Write the expression: _____________________ d. The sum of twice a number and 31

Define the variable: _____________________

Write the expression: _____________________

Example 3: Writing an equation

What does the word “is” suggest? _______________________

Track One Media sells all CDs for $12 each. Which equation best represents the cost c of a given number of n CDs? a. 12 + c = n b. n + 12 = c c. 12c = n d. c =12n

Relate: _____________ is _______ times ________________

Define: Let n = _______________________

Let c = _______________________

Write: ___________________

a. Suppose the manager at Track One Media raises the price of each SD to $15. Rewrite the equation to now find the cost of n CDs. b. Suppose the manager at Track One Media uses the equation c = 10.99

n What could this represent?

Example 4: Real World Problem Solving

Write an equation for the data in the table

1. Relate: ________ equals $20.00 minus

________

Cost of

Purchase

Change From

$20

20.00 $0

$19.00 $1.00

$17.50 $2.50

Define: Let c =

___________________________

$11.59 $8.41

Let a = ___________________________

Write: ___________________

2.Fill in the table and write an equation

Relate: ___________= _______/__

Define: Let e = ____________

Let s = ____________

Write: ___________________

$

$ Earned

$

$ Saved

$ $

$

$

$

$

Lesson 2-5 : Properties of Numbers

Properties of Real Numbers

Commutative Property of Addition/Multiplication a + b = b + a a

•b = b•a

Ex. 2 + 3 = 3 + 2 Ex. 2 •3=3•2

Associative Property of Addition/Multiplication

(a + b) + c = a + (b + c)

(a • b)•c = a•(b •c)

Distributive Property

Ex.

(2 + 3) + 4 = 2 + (3 + 4)

Ex.(2 •3)•4 = 2•(3•4) a(b + c)= ab + ac a(b

– c)= ab – ac

Ex. 2(3 + 4) = 2 •3 + 2•4

Ex. 2(3

– 4) = 2•3 - 2•4

Example 1: Identifying Properties

Name the property each illustrates. a. 9 + 7 = 7 + 9 b. (d

4)

3 = d

(4

3) c. (3+4) + 7 = 7 + (3 + 4) d. 6(a + b) = 6a + 6b e. (2

3)5 = 2(3

5) f. (-3 + 4) + 5 = -3 + (4 + 5) g. (3

8)0 = 3(8

0) h. 2(15 + 4)= 30 + 8 i. np=pn j. (p + q) + r = q + (p + r)

_________________

_________________

_________________

_________________

_________________

_________________

_________________

_________________

_________________

_________________

Example 3: Justifying steps

Simplify each expression and justify each step using a property or a basic operation. a. -4b + 9 + b

Steps

____________________

____________________

____________________

____________________

Reasons

____________________

____________________

____________________

____________________ b. 7z – 5(3 + z)

Steps

____________________

____________________

____________________

____________________

____________________

____________________

Reasons

____________________

____________________

____________________

____________________

____________________

____________________ c. 5a + 6 + a

Steps

____________________

____________________

____________________ d. 2(3t – 1) + 2

Reasons

____________________

____________________

____________________

Steps

____________________

____________________

____________________

____________________

Reasons

____________________

____________________

____________________

____________________

Lesson 2-4: Distributive Property

Define

Term: ________________________________________

Constant:_____________________________________

Coefficient:____________________________________

Like Terms: ____________________________________

Distributive Property (Pass it out)

For every real number a,b,and c. a(b + c) = ab + ac (b + c)a = ba + ca a(b – c) = ab – ac (b – c)a = ba – ca

Examples 5(20 + 6) = 5(20) + 5(6)

9(30-2) = 9(30) – 9(2)

(20 + 6)5 = 20(5) + 6(5)

(30 – 2)9 = 30(9) – 2(9)

Example 3: Simplifying an Expression

* an Algebraic expression in simplest form has no grouping symbols (parentheses)

Simplify each expression using the Distributive Property a. 2(5x + 3) b. (3b – 2)(1/3)

c. 2(3 – 7t) d. (0.4 + 1.1c) (3)

Example 4: Using the Multiplication Property of -1

To simplify

–(6x + 4) rewrite it as -1(6x + 4) and use the

Multiplication property of -1 and the distributive property to simplify

Simplify –(6x + 4) a. –(2x + 1) b. (3 – 8a) (-1)

Example 5: Combining Like terms (shape it up)

Examples of like terms: _______________________________

Examples of not like terms:_____________________________ a. 3x 2 + 5x 2 ____________________________ b. -5c + c ____________________________ c. 7y + 6y ____________________________ d. 3t – t ____________________________ e. -9w 3 – 3w 3 ____________________________ f. 8d + d ____________________________ g. 3t + 4t 2 – 2t 2 + 7t ____________________________ h. 4xy + 3y 2 – 2xy – 5 ____________________________

These phrases include two different operations so we must represent both of those operations in our expression. This represents the distributive property in word form.

“times the sum”, “times the difference”, times the quantity” a. Four times the sum of a number and 5 _________ b.Two times the difference of a number and 16 _________ c.Three times the quantity of a number added to 12 _________ d. 5 times the quantity of a number minus 10 _________

Lesson 5-7: Describing Number Patterns

Define:

Sequence: ____________________________________

Term: ________________________________________

Inductive Reasoning: ____________________________

Example 1: Using Inductive Reasoning

Use Inductive reasoning to describe each pattern. Then find the next two numbers. a.

2, 5, 8, 11… b.

2, 4, 8, 16… c.

1, 4, 9, 16… d.

9, 15, 21, 27…

Example 2: Using your calculator for multiple choice sequences

You can use the y= button on your calculator to help you determine the correct choice for a function representing a sequence.

A.

Which of the following function represents the sequence below?

{ 10, 12, 14, 16…}

First, build a table. The x variable represents the _________, and the y variable is the _______________.

X Y

Then check to see which function has a matching table set of values on the calculator. a.

F(x) = 3x + 7 b. F(x)= -2x + 12 c. F(x)= 2x + 8 d. F(x)=x + 9

What would be the value of f(8)= ________

What would the value of x if f(x)= 20? ____________

What would be the 11 th term in this sequence? __________

B.

Which expression best represents the following pattern?

X Y a.

2x -1 b.

3x c.

x 2 – x + 1 d.

x 2

What would f(6) = ___________

Draw the next pattern:

How many blocks would be in the pattern for the 15 th term?

Lesson # 3 –1 : Solving Two – Step Equations

Define

Variable___________________________________

Solve_____________________________________

Review: Order of Operations

P

E

_______________

_______________

M/D _______________

A/S _______________

Steps to Solve an Equation

1. Distribute

2. Combine like Terms

3. Letters to the Left and in

Front

4. What’s happening

5. Unwrap the steps

6. Check your answer using substitution

When we solve an equation we must look at the variable, decide what is happening to that variable using the order of operations, and then unwrap those steps.

Example 1: Solving a Two-Step Equation m

Solve: 10 = + 2 Check:

Solve: 7 = 2y – 3 Check:

Solve: -x + 15 = 12 Check:

Example 2: Real World Problem Solving a. A music store sells a copy of a deluxe electric guitar for $295. This is $30 more than 1/3 the cost of the electric guitar it is modeled after. What is the cost of the original deluxe electric guitar?

Relate:_____________ is _____ more than ____( _____________)

Define: Let c = _____________________________

Write: ____________________________________

Solve: Check: b. Suppose the Panther’s baseball team scored 5 runs Saturday’s game.this was four more than ½ the runs scored by the Lions’ team. How many runs did the Lions’ team score?

Relate: ____________ is ___ more than ___ (____________)

Define: Let L = ____________________

Write: ___________________________

Solve: Check:

Example 3: Writing a Function

In a catalog, tulips cost $0.75 each and shipping costs are $3.00. Write a rule that describes the amount of $ spent as a function of the number of tulip bulbs ordered.Then determine the greatest number of bulbs you can order for $14.

Relate: _______ = ______ ●_________ + ___________

Define: Let a = _________________

Write:___________________

Let b = _________________

If I can only spend $14, I need to substitute that number in for which variable and solve? ____________

Solve: Reasonable?: a. Suppose you have $25 to spend on tulips. What is the greatest number of bulbs you can order? b. Mrs. Simmons works at a furniture store. Her base salary is $125 a week plus 1/12 of her sales. Write a rule that describes her total weekly salary as a function of her sales. Then find the amount of her sales if her total weekly salary was $225.

Relate: _________ = ___________ plus _____ ( _____________)

Define: Let s = ___________________

Let p = ___________________

Write:___________________

If $225 is her pay, which variable do I need to substitute it for and solve?

________

Solve: Reasonable?:

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