This chapter reviews basic algebra concepts including the real number system, arithmetic operations, exponents, equations, and solving different types of problems. It emphasizes understanding key vocabulary, memorizing processes and properties, using provided formulas, asking questions when unsure, and checking work.
2. Section 1.1: The Real Number
System
SETS: collections of objects.
Natural Numbers Integers
Whole Numbers Positive Numbers
Rational Numbers Negative
Irrational Numbers Numbers
Real Numbers Even Numbers
Odd Numbers
Use { } {x | x > 5}
is read “the set of all x such that
x is greater than 5”
3. Section 1.1: The Real Number
System
GRAPHS: plot on the number line.
Individual numbers are dots
-3 -2 -1 0 1 2 3 4
4. Section 1.1: The Real Number
System
GRAPHS: plot on the number line.
Intervals including end points
-3 -2 -1 0 1 2 3 4
-3 -2 -1 0 1 2 3 4
5. Section 1.1: The Real Number
System
GRAPHS: plot on the number line.
Intervals not including end points
-3 -2 -1 0 1 2 3 4
-3 -2 -1 0 1 2 3 4
6. Section 1.2: Arithmetic & Properties of Real
Numbers
OPERATIONS:
Addition
Subtraction (the same as adding a
number with the opposite sign)
Multiplication
Division (the same as multiplying by
the reciprocal)
7. Section 1.2: Arithmetic & Properties of Real
Numbers
ADDITION:
Addends that have the same signs
Add absolute values
Keep the sign of the addends
Addends that have opposite signs
Subtract absolute values
Keep the sign of the addend with the
largest absolute value
8. Section 1.2: Arithmetic & Properties of Real
Numbers
MULTIPLICATION:
Multiply absolute values
If the factors have the same signs,
the product is positive
If the factors have opposite signs,
the product is negative
9. Section 1.2: Arithmetic & Properties of Real
Numbers
STATISTICS: measures of central tendency
Mean
Median
Mode
10. Section 1.2: Arithmetic & Properties of Real
Numbers
Properties:
Associative – addition, multiplication
Commutative – addition, multiplication
Distributive – multiplication is
distributed over addition
a (b + c) = ab + ac
11. Section 1.2: Arithmetic & Properties of Real
Numbers
Identities:
Addition – zero
Multiplication – one
Inverses:
Addition – opposites
Multiplication – reciprocals
12. Section 1.3: Definition of Exponents
EXPONENTS: repeated multiplication
In the expression: an
a is the base and n is the exponent
Exponents are NOT factors
Means to multiply “a” n times
13. Section 1.3: Definition of Exponents
ORDER OF OPERATIONS:
If an algebraic expression has more than one
operation, the following order applies:
1. Clear up any grouping.
2. Evaluate exponents.
3. Do multiplication and division from left to
right.
4. Do addition and subtraction from left to right.
14. Section 1.5: Solving Equations
Algebraic Expression vs. Equation
Expressions: a combination of
numbers and operations
Equation: a statement that two
expressions are equal
15. Section 1.5: Solving Equations
EXPRESSIONS:
Terms
Like terms
When multiplying, the terms do not
need to be alike
Can only add like terms!
16. Section 1.5: Solving Equations
TO SOLVE AN EQUATION IN ONE VARIABLE:
If you see fractions, multiply both sides by the LCD.
This will eliminate the fractions.
Simplify the algebraic expressions on each side of the
equal sign (eliminate parentheses and combine like
terms).
Use the addition property of equality to isolate the
variable terms from the constant terms on opposite
sides of the equal sign.
Use the multiplication property to make the coefficient
of the variable equal to one.
Check your results by evaluating.
17. Section 1.5: Solving Equations
TYPES OF EQUATIONS:
CONDITIONAL: if x equals this, then y
equals that.
IDENTITY: always true no matter what
numbers you use.
CONTRADICTION: never true no matter
what numbers you use.
FORMULAS: conditional equations that
model a relationship between the variables.
18. Section 1.6 & 1.7: Solving Problems, Applications
TYPES OF PROBLEMS:
Geometry
Percent
Physics (forces)
Uniform motion
Mixtures
Good ‘ole common sense analysis
19. Chapter 1: Basic Algebra Review
SUMMARY:
KNOW YOUR VOCABULARY! You can’t
follow directions if you don’t know what the
words in the instructions mean.
Memorize the processes and the properties.
I will provide formulas for your reference.
Ask questions if you are unsure.
Always check your work to make sure that
you answered the question, and that your
answer is reasonable.
Editor's Notes
X = 1
{ x | x > 2} and { x | 0 < x < 2}
{ x | x > 2} and { x | 0 < x < 2}
No need to have rules for subtraction, just add the opposite.
Division rules for the signs are the same. IMPORTANT: Division by zero is “undefined”.
meAn = Average medIan = mIddle mOde = mOst
Associative (grouping), Commutative (order) Distributive (must have two operations, not just one). Can be multiplication or division, and addition or subtraction.
Additive inverses: a and –a are inverses because when added, they equal the additive identity (zero). Multiplicative Inverses: reciprocals are inverses because when multiplied, they equal the multiplicative identity (one). Remember also, -(-a) = a. That is, the opposite of a negative number is a positive number with the same absolute value.
a 5 = a a a a a, not a 5
Remember, addition and subtraction are basically the same thing, so can’t do one or the other first. You can always change subtraction to addition by adding the opposite. Likewise for multiplication and division. You can change division to multiplying by the reciprocal.
2x + 5 is an algebraic expression as is a single number such as 9. 2x + 5 = 9 is an equation.
A term is the combination of numbers and variables between “+” signs. 2x – 8 has two terms: 2x and -8. The expression x + 5 contains two terms, x and 5. They are not alike because one is a variable, whereas 5 is a constant. Therefore, x + 5 is simplified. No further work is required. IMPORTANT: x + 5 does NOT equal 5x. 5x = x + x + x + x + x. To prove x + 5 = 5x is false, pick a number (other than zero and one) and evaluate the statement. For example, choose 2. 2 + 5 = 7; 5(2) = 10. Since 7 does not equal 10, we’ve proved x + 5 = 5x is false.
Example: 1 / 3 x + 4 = 2(x – 1)
The solution set for an identity is “all real numbers”, ℝ. The solution set for a contradiction is the empty set, . That is, it has no solution.