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Elementary Algebra 2e

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Chapter 1

Foundations

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Summary

Put commas in the number to separate the periods Draw 3 blanks to indicate the number of places needed in each period. Name the number in each period and place the digits in the correct place value position Locate the given place value and mark it with an arrow.

Key terms

absolute value
The absolute value of a number is its distance from 0 on the number line. The absolute value of a number n is written as | n |
denominator
The denominator is the value on the bottom part of the fraction that indicates the number of equal parts into which the whole has been divided
fraction
A fraction is written a b , where b ≠ 0 a is the numerator and b is the denominator. A fraction represents parts of a whole. The denominator b is the number of equal parts the…
irrational number
An irrational number is a number that cannot be written as the ratio of two integers. Its decimal form does not stop and does not repeat
number line
A number line is used to visualize numbers. The numbers on the number line get larger as they go from left to right, and smaller as they go from right to left
opposite
The opposite of a number is the number that is the same distance from zero on the number line but on the opposite side of zero: - a means the opposite of the number. The notation…
rational number
A rational number is a number of the form p q , where p and q are integers and q ≠ 0 . A rational number can be written as the ratio of two integers. Its decimal form stops or…

Chapter 2

Solving Linear Equations and Inequalities

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Summary

To Determine Whether a Number is a Solution to an Equation Step 1. Substitute the number in for the variable in the equation If it is not true, the number is not a solution

Key terms

Number
a Solution to an Equation Step 1
conditional equation
An equation that is true for one or more values of the variable and false for all other values of the variable is a conditional equation
identity
An equation that is true for any value of the variable is called an identity. The solution of an identity is all real numbers
contradiction
An equation that is false for all values of the variable is called a contradiction. A contradiction has no solution
solution of an equation
A solution of an equation is a value of a variable that makes a true statement when substituted into the equation

Chapter 3

Math Models

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Summary

Make sure all the words and ideas are understood Choose a variable to represent that quantity It may be helpful to restate the problem in one sentence with all the important information. Then, translate the English sentence into an algebra equation

Key terms

principal
The principal is the original amount of money invested or borrowed for a period of time at a specific interest rate
amount of discount
The amount of discount is the amount resulting when a discount rate is multiplied by the original price of an item
discount rate
The discount rate is the percent used to determine the amount of a discount, common in retail settings
rate of interest
The rate of interest is a percent of the principal, usually expressed as a percent per year
interest
Interest is the money that a bank pays its customers for keeping their money in the bank
mark-up
A mark-up is a percentage of the original cost used to increase the price of an item
original cost
The original cost in a retail setting, is the price that a retailer pays for an item
simple interest
Simple interest is the interest earned according to the formula I = P r t

Chapter 4

Graphs

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Summary

Solution of a Linear Equation An ordered pair ( x , y ) is a solution of the linear equation A x + B y = C , if the equation is a true statement when the x - and y - values of the ordered pair are substituted into the… Points with a y -coordinate equal to 0 are on the x -axis, and have coordinates ( a , 0 ) Sign Patterns of the Quadrants Quadrant I Quadrant II Quadrant III Quadrant IV ( x , y ) ( + , + ) ( - , - ) ( + , - ) Quadrant I Quadrant II Quadrant III Quadrant IV ( x , y ) ( + , + ) ( - , - ) ( + , - ) Points with an x -coordinate equal to 0 are on the y -axis, and have coordinates ( 0 , b )

Key terms

linear equation
A linear equation is of the form A x + B y = C , where A and B are not both zero, is called a linear equation in two variables
rectangular coordinate system
A grid system is used in algebra to show a relationship between two variables; also called the xy -plane or the ‘coordinate plane’
equation
a true statement when the x - and y - values of the ordered pair are substituted into the…
ordered pair
An ordered pair ( x , y ) gives the coordinates of a point in a rectangular coordinate system
quadrant
The x -axis and the y -axis divide a plane into four regions, called quadrants
y -coordinate
The second number in an ordered pair ( x , y )
y -coordinate equal to 0
on the x -axis, and have coordinates ( a , 0 )
x -coordinate equal to 0
on the y -axis, and have coordinates ( 0 , b )

Chapter 5

Systems of Linear Equations

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Summary

To solve a system of linear equations by graphing Step 1. Determine whether the lines intersect, are parallel, or are the same line If the lines intersect, identify the point of intersection. If the lines are parallel, the system has no solution.

Key terms

system of linear equations
When two or more linear equations are grouped together, they form a system of linear equations
lines
parallel, the system has no solution
dependent equations
Two equations are dependent if all the solutions of one equation are also solutions of the other equation
supplementary angles
Two angles are supplementary if the sum of the measures of their angles is 180 degrees
complementary angles
Two angles are complementary if the sum of the measures of their angles is 90 degrees
consistent system
A consistent system of equations is a system of equations with at least one solution
inconsistent system
An inconsistent system of equations is a system of equations with no solution

Chapter 6

Polynomials

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Summary

Monomial —A polynomial with exactly one term is called a monomial Trinomial —A polynomial with exactly three terms is called a trinomial Degree of a Polynomial The degree of a term is the sum of the exponents of its variables Polynomials polynomial —A monomial, or two or more monomials combined by addition or subtraction is a polynomial

Key terms

polynomial
A polynomial is a monomial, or two or more monomials combined by addition or subtraction
monomial
A monomial is a term of the form a x m , where a is a constant and m is a whole number; a monomial has exactly one term
degree of a polynomial
The degree of a polynomial is the highest degree of all its terms
degree of a term
The degree of a term is the exponent of its variable
trinomial
A trinomial is a polynomial with exactly three terms
binomial
A binomial is a polynomial with exactly two terms

Chapter 7

Factoring

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Summary

Finding the Greatest Common Factor (GCF): To find the GCF of two expressions: Step 1. Write all variables with exponents in expanded form List all factors—matching common factors in a column.

Key terms

factoring
Factoring is splitting a product into factors; in other words, it is the reverse process of multiplying
greatest common factor
The greatest common factor is the largest expression that is a factor of two or more expressions is the greatest common factor (GCF)
perfect square trinomials pattern
If a and b are real numbers, a 2 + 2 a b + b 2 = ( a + b ) 2 a 2 - 2 a b + b 2 = ( a - b ) 2 a 2 + 2 a b + b 2 = ( a + b ) 2 a 2 - 2 a b + b 2 = ( a - b ) 2
Zero Product Property
The Zero Product Property states that, if the product of two quantities is zero, at least one of the quantities is zero
prime polynomials
Polynomials that cannot be factored are prime polynomials
quadratic equations
are equations in which the variable is squared
difference of squares pattern
If a and b are real numbers,

Chapter 8

Rational Expressions and Equations

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Summary

Simplified Rational Expression A rational expression is considered simplified if there are no common factors in its numerator and denominator Opposites in a Rational Expression The opposite of a - b is b - a . Multiplication of Rational Expressions If p , q , r , s are polynomials where q ≠ 0 , s ≠ 0 , then p q · r s = p r q s To multiply rational expressions, multiply the numerators and multiply the denominators

Key terms

rational expression
A rational expression is an expression of the form p q , where p and q are polynomials and q ≠ 0
complex rational expression
A complex rational expression is a rational expression in which the numerator or denominator contains a rational expression
proportion
A proportion is an equation of the form a b = c d , where b ≠ 0 , d ≠ 0 . The proportion is read “ a is to b , as c is to d . ”
similar figures
Two figures are similar if the measures of their corresponding angles are equal and their corresponding sides are in the same ratio
rational equation
A rational equation is two rational expressions connected by an equal sign

Chapter 9

Roots and Radicals

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Summary

If a n is a real number and n ≥ 2 , a 1 n = a n For any positive integers m and n , a m n = ( a n ) m and a m n = a m n

Key terms

rational exponents
If a n is a real number and n ≥ 2 , a 1 n = a n . For any positive integers m and n , a m n = ( a n ) m and a m n = a m n
rationalizing the denominator
The process of converting a fraction with a radical in the denominator to an equivalent fraction whose denominator is an integer is called rationalizing the denominator
radical equation
An equation in which the variable is in the radicand of a square root is called a radical equation
like radicals
Radicals with the same index and same radicand are called like radicals
like square roots
Square roots with the same radicand are called like square roots
principal n th root
The principal n th root of a is written a n
square root of a number
If n 2 = m , then n is a square root of m

Chapter 10

Quadratic Equations

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Summary

Square Root Property If x 2 = k , and k ≥ 0 , then x = k or x = - k Quadratic Formula The solutions to a quadratic equation of the form a x 2 + b x + c = 0 , a ≠ 0 are given by the formula: x = - b ± b 2 - 4 a c 2 a Solve a Quadratic Equation Using the Quadratic Formula To solve a quadratic equation using the Quadratic Formula. Binomial Squares Pattern If a , b are real numbers, ( a + b ) 2 = a 2 + 2 a b + b 2 ( a - b ) 2 = a 2 - 2 a b + b 2

Key terms

quadratic equation
A quadratic equation is an equation of the form a x 2 + b x + c = 0 , where a ≠ 0
Square Root Property
The Square Root Property states that, if x 2 = k and k ≥ 0 , then x = k or x = - k
consecutive even integers
Consecutive even integers are even integers that follow right after one another. If an even integer is represented by n , the next consecutive even integer is n + 2 , and the…
consecutive odd integers
Consecutive odd integers are odd integers that follow right after one another. If an odd integer is represented by n , the next consecutive odd integer is n + 2 , and the next…
quadratic equation in two variables
A quadratic equation in two variables, where a , b , and c are real numbers and a ≠ 0 is an equation of the form y = a x 2 + b x + c
vertex
The point on the parabola that is on the axis of symmetry is called the vertex of the parabola; it is the lowest or highest point on the parabola, depending on whether the…
axis of symmetry
The axis of symmetry is the vertical line passing through the middle of the parabola y = a x 2 + b x + c
discriminant
In the Quadratic Formula, x = - b ± b 2 - 4 a c 2 a the quantity b 2 - 4 a c is called the discriminant

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