WGU C278 - College Algebra (missing most of Lessons 8)

Variable

This is a symbol (generally a letter) that is used to represent an unknown number or any one of several numbers.

Rational Numbers

This is any number that can be written in the form a/b where a and b are integers and b?0.
(The letter ? represents the whole set)

Irrational Numbers

This is any number that can be written as an infinite, non-repeating decimal. These cannot be written in fraction form.

Natural Numbers

These are counting numbers starting with the number 1. {1,2,3,4,5,6,...}
(The letter ? represents the whole set)

Whole Numbers

These are counting numbers starting with the number 0. {0,1,2,3,4,5,6,...}
(The letter ?? represents the whole set)

Integers

These are numbers that can be represented on a number line, no decimals. {..., ?4,?3,?2,?1,0,1,2,3,4,...}
(The letter ? represents the whole set)

Real numbers

Formed with the set of rational and irrational numbers.
(The letter ? represents the whole set)

Natural number relationships

Every one of these numbers is also a:
-whole number
-integer
-rational number
-real number

Whole number relationships

Every one of these numbers is also a:
-integer
-rational number
-real number

Integer relationships

Every one of these numbers is also a:
-rational number
-real number

Rational number relationships

Every one of these numbers is also a:
-real number

Irrational number relationships

Every one of these numbers is also a:
-real number

Real number line

Every rational and irrational number has a corresponding point on this line.

Order of Operations

PEMDAS (Please excuse my Dear Aunt Sally)
1. Parethesis (groups)
2. Exponentials
3. Multiplication and Division, left to right
4. Addition and Subtraction, left to right

?

an element of

?

such that

{x?x is an even integer}

the set of all x such that x is an even integer

<

less than

>

greater than

?

less than or equal to

?

greater than or equal to

{x?x??}

the set of all x such that x is an element of the set of integers

term

an expression that involves only multiplication and/or division with constants and/or variables.
Examples: 2x?, �/?x�y, 14, 5.6a

Conditional Equation

An equation with a finite number of solutions

Identity (Equation)

An equation with an infinite number of solutions

Contradiction (Equation)

An equation with no solutions

Applications (aka)

Word Problems (aka)

Formula for Distance

D=RT (Distance = Rate � Time)

Formula for Profit

P=S-C (Profit = Selling Price - Cost)

Formula for Simple Interest

I=PRT (Interest = Principle � Rate � Time)
I=PR (Interest = Principle � Rate) if just one year

Solve Equalities

What is done to one side of the equation must be done to the other

Solve Inequalities

--Multiply or Divide by a negative number results in an OPPOSITE inequality sign.
--All else keeps the inequality sign the same.

Slope-Intercept Form
(equation)

y=mx+b
(m is the slope and the y-intercept is (0,b))

Slope of the line
(equation)

(Slope (m) = Change in Y � Change in X = Rise � Run and x? ? y?)

Horizontal line

(0,#)
y=b
slope is 0

Vertical line

(#,0)
x=a
slope is 0

Slope

Rise � Run

Point-Slope Form
(equation)

y-y?=m(x-x?)

Standard Form
(equation)

ax+by=c

Parallel lines

Slope is identical
y=2x+1
y=2x+3

Perpendicular lines

Slope is the negative reciprocal
y=�x+1
y=-2x-3

Relation

Set of ordered pairs of real numbers

Domain (D)

The ___ of a relation is the set of all first coordinates in the relation.

Range (R)

The ___ of a relation is the set of all second coordinates in the relation.

Domain axis

The horizontal axis (x-axis) is called this

Range axis

The vertical axis (y-axis) is called this

Function (�)

-A relation in which each domain element has exactly one corresponding range element.
-A relation in which each first coordinate appears only once.
-A relation in which no two ordered pairs have the same first coordinate.

Vertical line test

if any vertical line intersects the graph of a relation at more than one point, then the relation is NOT a function

Linear function

A function represented by an equation of the form y=mx+b. The domain is the set of all real numbers DE=(-?,?)

Nonlinear function

y=2�x-1 (x?1)
D=(-?,1)?(1,?)

?
(A?B)

union symbol: meaning that the set belongs to either or to both. Think "or

?
(A?B)

intersection symbol: meaning all elements belong to both. Think "and

Closed interval notation

[ ] means includes the numbers listed
Example: [-3,2] means -3?x?2
Solid dot on a number line

Open interval notation

( ) means it excludes the number listed
Example (-1,4) means -1<x<4
open dot on the number line
the infinity symbol is always open in parenthesis

function notation
(formula)

�(x)=mx+b

System of equations
Set of simultaneous equations

Two or more linear equations considered at one time.

Consistent

two linear equations in two variables:
have exactly one solution (the lines intersect at one point)

Inconsistent

two linear equations in two variables:
have no solution (the lines are parallel)

Dependent

two linear equations in two variables:
have an infinite number of solutions (the same line)

Product Rules for Exponents

Add the exponents together

Quotient Rule for Exponents

(top exponent) minus (bottom exponent)

Rule for Negative Exponents

Reciprocal of the base.

Power Rule

Multiply the exponents

Power Rule of a Product

Raise each factor to that power

Power Rule of a Quotient (Fractions)

Raise the numerator and denominator to that power

Exponent Zero (0)

a?=1
0?=undefined

Exponent One (1)

a�=a

Negative base number without parenthesis

-x� = (-1)x�
Without parenthesis the base is not negative but is preceded by a -1

Negative base number in parenthesis

(-x)� = (-x)(-x)
With parenthesis the base is negative

Monomial

-n is a whole number
-k is a real number
-No variables or positive exponents in the denominator.
-No negative exponents in the numerator.
-No fractional exponents (only whole #s)

Degree of the monomial

n is called this
With more than one variable, this is sum of the exponents of its variable
A nonzero constant (such as 5) is considered to be monomial of degree 0.

Coefficient of the monomial

k is called this

Polynomial

monomial or the algebraic sum or difference of monomials

Degree of a polynomial

The largest of the degrees of its term after like terms have been combined.
With multiple exponents - use the largest one AFTER all like term are combined.

Leading coefficient (Coefficient of the polynomial)

The coefficient of the term of the largest degree.
(aka the coefficient of the term with the largest exponent)

Polynomial with *one* term
(after simplification)

Monomial
Example: 15x�
(3rd-degree monomial)

Polynomial with *two* terms
(after simplification)

Binomial
Example: 4x-10
(1st-degree binomial)

Polynomial with *three* terms
(after simplification)

Trinomial
Example: -x?+2x-1
(4th-degree trinomial)

Linear polynomial

Degree 0 or 1
Example: 3x+8
(1st-degree binomial, leading coefficient 3)

Quadratic polynomial

Degree 2
Example: 5x�-3x+7
(2nd-degree trinomial, leading coefficient 5)

Cubic polynomial

Degree 3
Example: -10y�
(3rd-degree monomial, leading coefficient -10)

Adding polynomials

Combine like terms
(written with highest degree aka. exponent first)

Subtracting polynomials

-Change the signs of the term being subtracted (positive to negative and vice versa)
-Combine like terms
(written with highest degree aka. exponent first)

Evaluation of Polynomials

P is the polynomial and x is the variable used in the polynomial.
P(3) means 3 is substituted for all x's

Distributive Property

Difference of Two squares

Sum of the same binomial terms *but* one is addition and one subtraction.

Perfect Square Trinomials
(Square of a binomial sum)

1. the first term is squared (first of the trinomial)
2. the coefficients of the two are multiplied and then doubled, stays positive (second of the trinomial)
3. the second term is squared (third of the trinomial)

Perfect Square Trinomials
(Square of a binomial difference)

1. the first term is squared (first of the trinomial)
2. the coefficients of the two are multiplied and then doubled, stays negative (second of the trinomial)
3. the second term is squared (third of the trinomial)

Squares of binomial - Common Error

FOIL Method

*F* irst terms
*O* utside terms
*I* nside terms
*L* ast terms

Dividing by a Monomial
(not covered in the course)

Divide each term in the numerator by the monomial in the denominator and simply each fraction.
(not covered in the course)

Factoring out the GCF
(find a monomial that is the GCF of a polynomial)

1. Find the variable(s) of highest degree and the largest integer coefficient that is a factor of each term of the polynomial. (This is one factor)
2. Divide this monomial factor into each term of the polynomial resulting in another polynomial factor.
(if

Not factorable
(irreducible or prime)

Polynomials that do not have a GCF (greatest common factor)

Second-degree trinomials
(in the variable x)

ax�+bx+c
(a, b, and c are real constants)

Factoring by grouping

Group polynomials with four or more terms in such a way that a common binomial factor or some other form of factors can be recognized.
Example: 2x�-20x-3x+30 = 2x(x-10)-3(x-10) = (x-10)(2x-3)
Always write the GCF first

Factor trinomial with leading coefficient 1

x�+bx+c
Find two factors of *c* whose sum is *b*.
(if they do not exist, the trinomial is not factorable)
Example: x�+11x+30 = (x+5)(x+6)

Trial-and-Error Method of Factoring with FOIL
(leading coefficient other than 1)

ax�+bx+c
-Find all possible combinations of factors of *ax�* and *c* in their respective *F* and *L* positions.
-Only check the sums in the *O* and *I* positions, until you find the sum to be *bx* (the middle term).
(if they do not exist, the trinomial is

ac-Method of Factoring trinomials
(leading coefficient other than 1)

ax�+bx+c
1.Multiply *a* & *c*
2.Find two integers whose product is *ac* and whose sum is *b*. (if none, then not factorable)
3.Rewrite the middle term *bx* using the two numbers from above as coefficients.
4.Factor by grouping the 1st two terms and the la

11�

121

12�

144

13�

169

14�

196

15�

225

16�

256

17�

289

18�

324

19�

361

20�

400

(x+a)(x-a) = ?

x�-a� = ?

(x+a)� = ?

x�+2ax+a� = ?

(x-a)� = ?

x�-2ax+a� = ?

Not factorable squares

x�+a� = *Not* factorable
(x-a)� = Factorable

Factoring Perfect Square Trinomials

In a perfect square trinomial, both the first and last terms of the trinomial must be perfect squares. If the first term is of the form x� and the last term is of the form a�, then the middle term must be of the form 2ax or ?2ax.
x�+2ax+a� = (x+a)�
x�-2ax

Difference of two squares

x�-a� = (x+a)(x-a)
The first binomial factor is addition, the second is subtraction.

Finding the Roots

Finding the Solutions to an equation

Quadratic equations

ax�+bx+c=0
a, b, and c are constants and a?0
(if a=1, then the answer is the 2 factors whose product is *c* and sum is *b*, check your positive/negative signs)

Zero-factor Property

if ab = 0, then a=0 or b=0 or both.
Before factoring out anything, get everything one one side of the equals side so it equals 0

Double root
(root of multiplicity two)

If you have a double factor, then the solution is called ____.
Equation: (x+1)(x+1)=0
Answer = -1 (doubled)

Factor Theorem

If x=c is a root of a polynomial equation in the form P(x)=0, then x-x is a factor of the polynomial P(x).

Consecutive Integers

Integers are _______ if each is 1 more than the previous integer. Three of these can be represented by n, n+1, n+2.
Example: 5,6,7

Consecutive Even Integers

These integers are _______ if each is 2 more than the previous even integer. Three of these can be represented by n, n+2, n+4.
Example: 24, 26, 28

Consecutive Odd Integers

These integers are _______ if each is 2 more than the previous odd integer. Three of these can be represented by n, n+2, n+4.
Examples: 41,43,45

Pythagorean Theorem

c�=a�+b�
The square of the hypotenuse is equal to the sum of the squares of the legs.

Hypotenuse

The longest side of a right triangle.

Rational Expression

If the denominator becomes 0 because of substituting a variable, then the expression is undefined.

Restrictions on the variable.

The undefined value of the variable.

Fundamental Principle of Fractions

Reciprocal of a fraction

Flip the fraction upside down. Multiplying a fraction by its reciprocal = 1

Multiplication of a fraction

Multiply all the numerators, multiply all the denominators.

Division of a fraction

Copy, Dot, Flip"
Multiply the first fraction by the reciprocal of the second.

Addition of a fraction

The denominators must match, then add the denominators together

Subtraction of a fraction

The denominators must match, then subtract the second denominator from the first.

Opposites in Rational Expressions

When nonzero opposites are divided, the quotient is always -1.

Common Error in Rational Expressions

Multiply Rational Expressions

1. Completely factor each numerator and denominator.
2. Multiply the numerators, multiply the denominators, keeping it in a factored form.
3. "Divide Out" any common factors, no denominator can be 0.

Divide Rational Expressions

1. Copy. Dot. Flip
2. Completely factor each numerator and denominator.
3. Multiply the numerators, multiply the denominators, keeping it in a factored form.
4. "Divide Out" any common factors, no denominator can be 0.

Add Rational Expressions

1. Completely factor each numerator and denominator.
2. Add the numerators
3. Keep the common denominators

LCM for a set of polynomials

1. Completely factor each polynomial (including prime factors for numerical factors)
2. Form the product of all factors that appear, using each factor the most number of times it appears in any one polynomial

Adding Rational expressions with different denominators

1. Find the LDC (the LCM of the denominators)
2. Rewrite each fraction in an equivalent form with the LCD as the denominator
3. Add the numerators and keep the common denominator
4. Reduce if possible

Placement of Negative Signs

Subtraction with Rational Expressions

Common Error when subtracting rational expressions

Ratios

Proportion

An equation stating that two ratios are equal

Word problems with proportions

Use the correct ration of units on both sides. One of the following conditions must be true:
1. Numerators agree in type AND denominators agree in type
-or-
2. Numerators correspond AND denominators correspond

Similar triangles

Must meet BOTH conditions
1. The corresponding angles are equal
2. The corresponding sides are proportional

Solve an Equation containing rational expressions

1. Find the LCM of the denominators
2. Multiply both sides of the equation by the LCM and simplify
3. Solve the resulting equation (this will have only polynomials on both sides)
4. Check each solution in the original equation (any solution with a 0 denom

Word problems related to hours worked

A man can dig a ditch in 3 hours, what can he do in 1 hour = 1/3

Equation for Distance, Rate, and Time

d=rt

Finding the square root

Radical sign

Radicand

The number under the Radical sign

Radical
or
Radical Expression

Principal square root

Positive square root of a positive real number

Square Root

Mistakes made with Square Roots and Radical Expressions

Square root of x�

Index

Square roots with expressions with even and odd exponents

Cube root

Types of roots

Complex number

i and i�
(Complex numbers)

Square root of a negative number
(Complex numbers)

Number Types

Equations with Complex Numbers

Addition & Subtraction with Complex Numbers

Common Error when multiplying Complex Numbers

Multiplication with Complex Numbers

1. FOIL
2. Simplify
3. Standard Form

Conjugate

(a+b) and (a-b) are called this

Division with Complex Numbers

1. Multiply both the numerator and denominator by the complex conjugate of the denominator.
2. Simplify the resulting products in both the numerator and denominator.
3. Write in standard form.

Powers of i

Only 4 answers
1
-1
i
-i

i� =
i? =
i? =
i�� =

1

i� =
i? =
i�? =

-1

i� =
i? =
i�� =

-i

i? =
i? =

i

Factoring two squares
(Example: x�+9)
(Factoring Complex Numbers)

This is "not factorable" using real factors, but can be factored with complex conjugates.

Solving Quadratic Equations using Square Root Property

Quadratic Formula
(used to solve ax�+bx+c=0)

Quadratic Formula common mistakes

Quadratic Formula, solving the discriminant
(b�-4ac)

Projectile Formula

h = height of object, in feet
t = time (seconds) the object is in the air
v? = beginning velocity, (feet per second)
h? = beginning height (0 if start from ground)
(This BETTER not be on the test)

Volume of a box formula

V=lwh
(Volume = Length x width x height)

Quadratic functions

y=ax�+bx+c
A function that can be written in the form above. Every graph of this function is a parabola.

Parabola

Graphs that have a curve
Example here is y=x�-4x+3

Vertex

the "turning point" of a parabola
Example here is (2,-1)

Line of Symmetry
(axis of symmetry)

the line that passes through the vertex and creates the mirror image
Example here is x=2

y=ax�
(items to remember when graphing)

domain: x|x is any real number
vertex: (0,0)
line of symmetry: x=0 (y-axis)
bigger |a|: narrower the opening
smaller |a|: wider the opening
if a>0, the parabola opens upward
if a<0, the parabola opens downward

y=ax�+k
(items to remember when graphing)

k creates a vertical shift
domain: x|x is any real number
vertex: (0,k)
line of symmetry: x=0 (y-axis)
bigger |a|: narrower the opening
smaller |a|: wider the opening
if a>0, the parabola opens upward
if a<0, the parabola opens downward

y=a(x-h)�
(items to remember when graphing)

h creates a horizontal shift
domain: x|x is any real number
vertex: (h,0)
line of symmetry: x=h
bigger |a|: narrower the opening
smaller |a|: wider the opening
if a>0, the parabola opens upward
if a<0, the parabola opens downward

y=a(x-h)� +k
(items to remember when graphing)

vertical and horizontal shifts
domain: x|x is any real number
vertex: (h,k)
line of symmetry: x=h
bigger |a|: narrower the opening
smaller |a|: wider the opening
if a>0, the parabola opens upward
if a<0, the parabola opens downward

y=ax�+bx+c
(items to remember when graphing)

Change into form y=a(x-h)�+k
once in this form, you can easily find the vertex, line of symmetry and range

Minimum and Maximum values

Exponents that are fractions
(Example 6 to the � power)

Exponents to the nth

Radical Notation

General Form of Fraction Exponents
and Radical Notation

Sum of two functions

Difference of two functions

Product of two functions

Quotient of two functions

Composite function
&
Domain of that function

One-to-one functions
(1-1 functions)

each value of y in the range must only have one corresponding value of x in the domain.
(x,y) meaning for each y, there are no duplicate x's

Horizontal line test

A function is a one-to-one if not horizontal line intersects the graph of a the function at more than one point.

Inverse functions

if � is a one-to-one function with (x,y)
the the inverse �?� is also one-to-one with (y,x)

To determine whether two functions are inverses

Finding the Inverse of a one-to-one function