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Transcript
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CHAPTER
1
Family Letter
Section A
What We Are Learning
Dear Family,
Equations and
Inequalities
Your child will be learning about equations and inequalities.
Initially, your child will be evaluating algebraic expressions that
contain up to two variables. When given the values of the
variables, your child will simply “substitute” those values for the
intended variable and then simplify the expression. This skill
will help your child check their answers when solving
equations.
Vocabulary
These are the math words
we are learning:
Addition Property of
Equality Add the same
number to both sides of an
equation, and the new
equation will have the
same solution.
Algebraic Expression
An expression with one or
more variables.
Algebraic Inequality An
inequality that contains a
variable.
Another skill your child will be reviewing is writing algebraic
expressions in place of word phrases. Listed below are
examples of the four basic operations and some key phrases
that may help your child write these algebraic expressions.
Operation
Key Word Phrases
Addition
Subtraction
Coefficient The number
multiplied by the variable.
Constant A value that
does not change.
Division Property of
Equality Divide both
sides of the equation by
the same number and the
new equation will have the
same solution.
Equation A mathematical
sentence that contains an
equal sign.
Equivalent Expression
Expressions that have the
same value for all the
values of the variables.
Evaluate To find the
value of a numerical or
algebraic expression.
Inequality A statement
comparing expressions
that are not equal.
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Expression
a number plus 6
add 6 to a number
the sum of 6 and a number
6 more than a number
6m
a number minus 3
3 less than a number
a number decreased by 3
the difference of a number
and 3
m3
Multiplication
8 times a number
the product of a number and 8
Division
a number divided by 2
m
2 divided into a number
m 2 or 2
the quotient of a number and 2
8m
Your child needs to be very familiar with the four basic
operations and how each operation works. This is a basic
building block for solving equations, another concept your child
will be learning in this section.
To effectively solve equations, your child will learn the four
equality properties: addition, subtraction, multiplication, and
division. These properties are also known as inverse
operations. Your child will use these properties to isolate the
variable in order to solve an equation.
An important element to equation solving is for students to
always check the solution. As you help your child with his or
her homework, make sure he or she does not forget this very
important step.
1
Holt Pre-Algebra
Holt Middle
School Math
<< Back <<
CHAPTER
1
|| Print ||
Family Letter
Section A, continued
Inverse Operation
Operations that “undo”
each other.
Isolate the Variable
Getting the variable alone
on one side of the equal
sign.
Like Term Terms that
have the same variable
raised to the same power.
Multiplication Property
of Equality Multiply both
sides of an equation by
the same number and the
statement will still be true.
Simplify Perform all the
operations possible,
including combining like
terms.
Solution The value of the
variable that makes the
equation true.
Solution of an Inequality
A number that makes an
inequality true.
Solution Set The set of
all solutions that make the
statement true.
Solve Find the value of
the variable that makes
the equation true.
Subtraction Property of
Equality Subtract the
same number from both
sides of the equation and
the statement will still be
true.
This is how your child will use the properties of equality to
solve a simple two-step equation.
Solve 4x 3 15.
4x 3 15
3 3
4x 12
Subtract 3 from both sides using the
Subtraction Property of Equality to
isolate the x-term.
4x
12
4
4
Divide both sides by 4 using the
Division Property of Equality in order
to completely isolate the variable, x.
x3
Check:
?
4x 3 15
?
4(3) 3 15
Substitute 3 for x.
?
12 3 15
15 15 After equation solving, your child will transition to solving and
graphing inequalities. The same steps will be followed to isolate
a variable in an inequality as with an equation. The difference
will be in the solution set. Your child will graph the solution to
the inequality on a number line.
Finally, your child will learn how to combine like terms in order
to simplify an expression. Combining like terms is an important
concept for your child to grasp. Your child will learn that just
because he or she changes the way an expression looks, the
value of the expression stays the same. For example:
Combine like terms.
6x 8y 9x
6x 8y 9x
6x 9x 8y
15x 8y
Identify like terms.
Rearrange the expression.
Add the coefficients of like terms.
This review of algebraic concepts will give your child the
confidence and skills needed to be successful in the chapters
to follow.
Sincerely,
Term Elements of an
expression that are
separated by plus or
minus signs.
Variable A letter that
represents a value that
can change or vary.
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
2
Holt Pre-Algebra
Holt Middle
School Math
Answer Key
|| Print ||
4
Click Here
Name
CHAPTER
1
Date
Class
Family Letter
Equations and Inequalities
Evaluate each expression for the given value(s) of the variable.
1. 8(x 7) for x 17
2. 6m 7n for m 12 and n 7
Write an algebraic expression for each word phrase.
3. a number decreased by 5
4. the product of a number and 9, less 4
Determine which value of the variable is a solution of the equation.
5. c 5 61; c 46, 56, or 66
6. d 37 12; d 39, 49, or 59
Solve.
7. 19 w 4
p
10. 7 9
8. 3x 42
9. 3n 2 11
11. 8 a 7
12. 16s 48
Use or to complete each inequality.
13. 3 5
10
14. (3)5
16
15. 6.1
1.5(4)
Combine like terms.
16. 3x 6v 5x 3v 8
17. 4s 3s 2 5j 9s 7j
Simplify.
18. 8(5 s) 2s
19. 2(4y 2) 7
Solve.
20. 5w 3w 16
21. 12x 7x 25
Answers: 1. 192 2. 23 3. n 5 4. 9n 4 5. c 56 6. d 49 7. w 23 8. x 14 9. n 3 10. p 63
11. a 15 12. s 3 13. 14. 15. 16. 8x 3v 8 17. 10s 12j 2 18. 40 6s 19. 8y 3
20. w 2 21. x 5
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Copyright © by Holt, Rinehart and Winston.
All rights reserved.
3
Holt Middle
School Math
Holt Pre-Algebra
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Name
CHAPTER
1
Date
Class
Family Fun
Hidden Math Terms
Directions
Find the hidden math terms from this section. The terms may be written
backwards, forwards, or on a diagonal. For fun, make copies of the puzzle
and give it to a friend or family member. Time how long it takes each
person to find all of the terms.
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ALGEBRAIC EXPRESSION
ALGEBRAIC INEQUALITY
COEFFICIENT
CONSTANT
EQUATION
EQUIVALENT EXPRESSIONS
EVALUATE
INEQUALITY
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
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INVERSE OPERATIONS
ISOLATE THE VARIABLE
LIKE TERMS
SIMPLIFY
SOLUTION
SOLVE
SUBSTITUTE
VARIABLE
4
Holt Pre-Algebra
Holt Middle
School Math