<< Chapter < Page Chapter >> Page >
This module is from Elementary Algebra by Denny Burzynski and Wade Ellis, Jr. The basic operations with real numbers are presented in this chapter. The concept of absolute value is discussed both geometrically and symbolically. The geometric presentation offers a visual understanding of the meaning of |x|. The symbolic presentation includes a literal explanation of how to use the definition. Negative exponents are developed, using reciprocals and the rules of exponents the student has already learned. Scientific notation is also included, using unique and real-life examples.Objectives of this module: be familiar with positive and negative numbers and with the concept of opposites.

Overview

  • Positive and Negative Numbers
  • Opposites

Positive and negative numbers

When we studied the number line in Section [link] we noted that

Each point on the number line corresponds to a real number, and each real number is located at a unique point on the number line.

A number line with arrows on each end, labeled from negative six to six in increments of one. There are two closed circles at negative two and four, respectively.

Positive and negative numbers

Each real number has a sign inherently associated with it. A real number is said to be a positive number if it is located to the right of 0 on the number line. It is a negative number if it is located to the left of 0 on the number line.

The notation of signed numbers

A number is denoted as positive if it is directly preceded by a " + " sign or no sign at all.
A number is denoted as negative if it is directly preceded by a " " sign.

The " + " and " - " signs now have two meanings:

+ can denote the operation of addition or a positive number.
can denote the operation of subtraction or a negative number.

Read the "-" Sign as "negative"

To avoid any confusion between "sign" and "operation," it is preferable to read the sign of a number as "positive" or "negative."

Sample set a

8 should be read as "negative eight" rather than "minus eight."

Got questions? Get instant answers now!

4 + ( 2 ) should be read as "four plus negative two" rather than "four plus minus two."

Got questions? Get instant answers now!

6 + ( 3 ) should be read as "negative six plus negative three" rather than "minus six plusminus three."

Got questions? Get instant answers now!

15 ( 6 ) should be read as "negative fifteen minus negative six" rather than "minus fifteenminus minus six."

Got questions? Get instant answers now!

5 + 7 should be read as "negative five plus seven" rather than "minus five plus seven."

Got questions? Get instant answers now!

0 2 should be read as "zero minus two."

Got questions? Get instant answers now!

Practice set a

Write each expression in words.

7 + ( 4 )

seven plus negative four

Got questions? Get instant answers now!

9 + 2

negative nine plus two

Got questions? Get instant answers now!

16 ( + 8 )

negative sixteen minus positive eight

Got questions? Get instant answers now!

1 ( 9 )

negative one minus negative nine

Got questions? Get instant answers now!

0 + ( 7 )

zero plus negative seven

Got questions? Get instant answers now!

Opposites

Opposites

On the number line, each real number has an image on the opposite side of 0. For this reason we say that each real number has an opposite. Opposites are the same distance from zero but have opposite signs.

The opposite of a real number is denoted by placing a negative sign directly in front of the number. Thus, if a is any real number, then a is its opposite. Notice that the letter a is a variable. Thus, " a " need not be positive, and " a " need not be negative.

If a is a real number, a is opposite a on the number line and a is opposite a on the number line.

Two number lines with arrows on each end. The first number line has three labels, zero at the center, negative a to the left of zero and a to the right of zero. Negative a and a are equidistant from zero. The second line has three labels, zero at the center, a to the left of zero and negative a to the right of zero. The points a and negative a are equidistant from zero.

( a ) is opposite a on the number line. This implies that ( a ) = a .

This property of opposites suggests the double-negative property for real numbers.

The double-negative property

If a is a real number, then
( a ) = a

Sample set b

If a = 3 , then a = 3 and ( a ) = ( 3 ) = 3 .

A number line with arrows on each end, labeled from negative three to three in increments of three. Negative three is labeled as negative a, and three is labeled as a. There is an additional label for three as the opposite of negative a.

Got questions? Get instant answers now!

If a = 4 , then a = ( 4 ) = 4 and ( a ) = a = 4 .

A number line with arrows on each end, labeled from negative four to four in increments of three. Negative four is labeled as a, and four is labeled as negative a. There is an additional label for negative four as the opposite of negative a.

Got questions? Get instant answers now!

Practice set b

Find the opposite of each real number.

( 1 )

1 , since ( 1 ) = 1

Got questions? Get instant answers now!

Suppose that a is a positive number. What type of number is a ?

If a is positive, a is negative.

Got questions? Get instant answers now!

Suppose that a is a negative number. What type of number is a ?

If a is negative, a is positive.

Got questions? Get instant answers now!

Suppose we do not know the sign of the number m . Can we say that m is positive, negative, or that we do notknow ?

We must say that we do not know.

Got questions? Get instant answers now!

Exercises

A number is denoted as positive if it is directly preceded by ____________________ .

a plus sign or no sign at all

Got questions? Get instant answers now!

A number is denoted as negative if it is directly preceded by ____________________ .

Got questions? Get instant answers now!

For the following problems, how should the real numbers be read ? (Write in words.)

( 4 )

negative negative four

Got questions? Get instant answers now!

For the following problems, write the expressions in words.

11 + ( 2 )

eleven plus negative two

Got questions? Get instant answers now!

6 ( 8 )

six minus negative eight

Got questions? Get instant answers now!

Rewrite the following problems in a simpler form.

( 8 )

( 8 ) = 8

Got questions? Get instant answers now!

[ ( 3 ) ]

3

Got questions? Get instant answers now!

[ ( 6 ) ]

6

Got questions? Get instant answers now!

{ [ ( 26 ) ] }

26

Got questions? Get instant answers now!

{ [ ( 11 ) ] }

Got questions? Get instant answers now!

{ [ ( 31 ) ] }

31

Got questions? Get instant answers now!

{ [ ( 14 ) ] }

Got questions? Get instant answers now!

5 ( 2 )

5 ( 2 ) = 5 + 2 = 7

Got questions? Get instant answers now!

6 ( 3 ) ( 4 )

13

Got questions? Get instant answers now!

2 ( 1 ) ( 8 )

Got questions? Get instant answers now!

15 ( 6 ) ( 5 )

26

Got questions? Get instant answers now!

24 ( 8 ) ( 13 )

Got questions? Get instant answers now!

Exercises for review

( [link] ) There is only one real number for which ( 5 a ) 2 = 5 a 2 . What is the number?

0

Got questions? Get instant answers now!

( [link] ) Simplify ( 3 x y ) ( 2 x 2 y 3 ) ( 4 x 2 y 4 ) .

Got questions? Get instant answers now!

( [link] ) Simplify x n + 3 x 5 .

x n + 8

Got questions? Get instant answers now!

( [link] ) Simplify ( a 3 b 2 c 4 ) 4 .

Got questions? Get instant answers now!

( [link] ) Simplify ( 4 a 2 b 3 x y 3 ) 2 .

16 a 4 b 2 9 x 2 y 6

Got questions? Get instant answers now!

Questions & Answers

differentiate between demand and supply giving examples
Lambiv Reply
differentiated between demand and supply using examples
Lambiv
what is labour ?
Lambiv
how will I do?
Venny Reply
how is the graph works?I don't fully understand
Rezat Reply
information
Eliyee
devaluation
Eliyee
t
WARKISA
hi guys good evening to all
Lambiv
multiple choice question
Aster Reply
appreciation
Eliyee
explain perfect market
Lindiwe Reply
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
Ezea
What is ceteris paribus?
Shukri Reply
other things being equal
AI-Robot
When MP₁ becomes negative, TP start to decline. Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
Kelo
Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
Kelo
yes,thank you
Shukri
Can I ask you other question?
Shukri
what is monopoly mean?
Habtamu Reply
What is different between quantity demand and demand?
Shukri Reply
Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
Ezea
ok
Shukri
how do you save a country economic situation when it's falling apart
Lilia Reply
what is the difference between economic growth and development
Fiker Reply
Economic growth as an increase in the production and consumption of goods and services within an economy.but Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
Shukri
production function means
Jabir
What do you think is more important to focus on when considering inequality ?
Abdisa Reply
any question about economics?
Awais Reply
sir...I just want to ask one question... Define the term contract curve? if you are free please help me to find this answer 🙏
Asui
it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
Awais
thank you so much 👍 sir
Asui
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
Cornelius
Suppose a consumer consuming two commodities X and Y has The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50. A,Calculate quantities of x and y which maximize utility. B,Calculate value of Lagrange multiplier. C,Calculate quantities of X and Y consumed with a given price. D,alculate optimum level of output .
Feyisa Reply
Answer
Feyisa
c
Jabir
the market for lemon has 10 potential consumers, each having an individual demand curve p=101-10Qi, where p is price in dollar's per cup and Qi is the number of cups demanded per week by the i th consumer.Find the market demand curve using algebra. Draw an individual demand curve and the market dema
Gsbwnw Reply
suppose the production function is given by ( L, K)=L¼K¾.assuming capital is fixed find APL and MPL. consider the following short run production function:Q=6L²-0.4L³ a) find the value of L that maximizes output b)find the value of L that maximizes marginal product
Abdureman
types of unemployment
Yomi Reply
What is the difference between perfect competition and monopolistic competition?
Mohammed
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Elementary algebra' conversation and receive update notifications?

Ask