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This module is from Elementary Algebra by Denny Burzynski and Wade Ellis, Jr. In this chapter, the emphasis is on the mechanics of equation solving, which clearly explains how to isolate a variable. The goal is to help the student feel more comfortable with solving applied problems. Ample opportunity is provided for the student to practice translating words to symbols, which is an important part of the "Five-Step Method" of solving applied problems (discussed in modules (<link document="m21980"/>) and (<link document="m21979"/>)). This module provides a summary of the key concepts of the chapter "Solving Linear Equations and Inequalities".

Summary of key concepts

Identity ( [link] )

An equation that is true for all acceptable values of the variable is called identity . x + 3 = x + 3 is an identity.

Contradiction ( [link] )

Contradictions are equations that are never true regardless of the value substituted for the variable. x + 1 = x is a contradiction.

Conditional equation ( [link] )

An equation whose truth is conditional upon the value selected for the variable is called a conditional equation .

Solutions and solving an equation ( [link] )

The collection of values that make an equation true are called the solutions of the equation. An equation is said to be solved when all its solutions have been found.

Equivalent equations ( [link] , [link] )

Equations that have precisely the same collection of solutions are called equivalent equations .
An equivalent equation can be obtained from a particular equation by applying the same binary operation to both sides of the equation, that is,
  1. adding or subtracting the same number to or from both sides of that particular equation.
  2. multiplying or dividing both sides of that particular equation by the same non-zero number.

Literal equation ( [link] )

A literal equation is an equation that is composed of more than one variable.

Recognizing an identity ( [link] )

If, when solving an equation, all the variables are eliminated and a true statement results, the equation is an identity .

Recognizing a contradiction ( [link] )

If, when solving an equation, all the variables are eliminated and a false statement results, the equation is a contradiction .

Translating from verbal to mathematical expressions ( [link] )

When solving word problems it is absolutely necessary to know how certain words translate into mathematical symbols.

Five-step method for solving word problems ( [link] )

  1. Let x (or some other letter) represent the unknown quantity.
  2. Translate the words to mathematics and form an equation. A diagram may be helpful.
  3. Solve the equation.
  4. Check the solution by substituting the result into the original statement of the problem.
  5. Write a conclusion.

Linear inequality ( [link] )

A linear inequality is a mathematical statement that one linear expression is greater than or less than another linear expression.

Inequality notation ( [link] )

> Strictly greater than < Strictly less than Greater than or equal to Less than equal to

Compound inequality ( [link] )

An inequality of the form

a < x < b

is called a compound inequality .

Solution to an equation in two variables and ordered pairs ( [link] )

A pair of values that when substituted into an equation in two variables produces a true statement is called a solution to the equation in two variables. These values are commonly written as an ordered pair . The expression ( a , b ) is an ordered pair. In an ordered pair, the independent variable is written first and the dependent variable is written second.

Questions & Answers

if three forces F1.f2 .f3 act at a point on a Cartesian plane in the daigram .....so if the question says write down the x and y components ..... I really don't understand
Syamthanda Reply
hey , can you please explain oxidation reaction & redox ?
Boitumelo Reply
hey , can you please explain oxidation reaction and redox ?
Boitumelo
for grade 12 or grade 11?
Sibulele
the value of V1 and V2
Tumelo Reply
advantages of electrons in a circuit
Rethabile Reply
we're do you find electromagnetism past papers
Ntombifuthi
what a normal force
Tholulwazi Reply
it is the force or component of the force that the surface exert on an object incontact with it and which acts perpendicular to the surface
Sihle
what is physics?
Petrus Reply
what is the half reaction of Potassium and chlorine
Anna Reply
how to calculate coefficient of static friction
Lisa Reply
how to calculate static friction
Lisa
How to calculate a current
Tumelo
how to calculate the magnitude of horizontal component of the applied force
Mogano
How to calculate force
Monambi
a structure of a thermocouple used to measure inner temperature
Anna Reply
a fixed gas of a mass is held at standard pressure temperature of 15 degrees Celsius .Calculate the temperature of the gas in Celsius if the pressure is changed to 2×10 to the power 4
Amahle Reply
How is energy being used in bonding?
Raymond Reply
what is acceleration
Syamthanda Reply
a rate of change in velocity of an object whith respect to time
Khuthadzo
how can we find the moment of torque of a circular object
Kidist
Acceleration is a rate of change in velocity.
Justice
t =r×f
Khuthadzo
how to calculate tension by substitution
Precious Reply
hi
Shongi
hi
Leago
use fnet method. how many obects are being calculated ?
Khuthadzo
khuthadzo hii
Hulisani
how to calculate acceleration and tension force
Lungile Reply
you use Fnet equals ma , newtoms second law formula
Masego
please help me with vectors in two dimensions
Mulaudzi Reply
how to calculate normal force
Mulaudzi
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Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
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