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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"/>)). Objectives of this module: be comfortable with combining techniques in equation solving, be able to recognize identities and contradictions.

Overview

  • Combining Techniques in Equation Solving
  • Recognizing Identities and Contrdictions

Combining techniques in equation solving

In Sections [link] and [link] we worked with techniques that involved the use of addition, subtraction, multiplication, and division to solve equations. We can combine these techniques to solve more complicated equations. To do so, it is helpful to recall that an equation is solved for a particular variable when all other numbers and/or letters have been disassociated from it and it is alone on one side of the equal sign. We will also note that

To associate numbers and letters we use the order of operations.

  1. Multiply/divide
  2. Add/subtract

To undo an association between numbers and letters we use the order of operations in reverse.

  1. Add/subtract
  2. Multiply/divide

Sample set a

Solve 4 x 7 = 9 for x .

4 x 7 = 9 First, undo the association between x and 7. The 7 is associated with x by subtraction . Undo the association by adding 7 to b o t h sides . 4 x 7 + 7 = 9 + 7 4 x = 16 Now, undo the association between x and 4. The 4 is associated with x by multiplication . Undo the association by dividing b o t h sides by 4. 4 x 4 = 16 4 16 7 = 9 Is this correct? x = 4

C h e c k : 4 ( 4 ) 7 = 9 Is this correct? 9 = 9 Yes, this is correct .

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Solve 3 y 4 5 = 11.

3 y 4 5 = 11 5 is associated with y by subtraction . Undo the association by adding 5 to b o t h sides . 3 y 4 5 + 5 = 11 + 5 3 y 4 = 6 4 is associated with y by division . Undo the association by multiplying b o t h sides by 4. 4 3 y 4 = 4 ( 6 ) 4 3 y 4 = 4 ( 6 ) 3 y = 24 3 is associated with y by multiplication . Undo the association by dividing b o t h sides by 3. 3 y 3 = 24 3 3 y 3 = 8 y = 8

C h e c k : 3 ( 8 ) 4 5 = 11 Is this correct? 24 4 5 = 11 Is this correct? 6 5 = 11 Is this correct? 11 = 11 Yes, this is correct .

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Solve 8 a 3 b + 2 m = 6 m 5 for a .

8 a 3 b + 2 m = 6 m - 5 2 m is associated with a by addition . Undo the association by subtracting 2 m from b o t h sides . 8 a 3 b + 2 m - 2 m = 6 m - 5 - 2 m 8 a 3 b = 4 m - 5 3 b a s s o c i a t e d w i t h a by division . Undo the association by multiplying b o t h sides by 3 b . ( 3 b ) ( 8 a 3 b ) = 3 b ( 4 m - 5 ) 8 a = 12 b m - 15 b 8 is associated with a by multiplication . Undo the multiplication by dividing b o t h sides by 8. 8 a 8 = 12 b m - 15 b 8 a = 12 b m - 15 b 8

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Practice set a

Solve 3 y 1 = 11 for y .

y = 4

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Solve 5 m 2 + 6 = 1 for m .

m = 2

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Solve 2 n + 3 m = 4 for n .

n = 4 3 m 2

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Solve 9 k 2 h + 5 = p 2 for k .

k = 2 h p 14 h 9

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Sometimes when solving an equation it is necessary to simplify the expressions composing it.

Sample set b

Solve 4 x + 1 3 x = ( 2 ) ( 4 ) for x .

4 x + 1 3 x = ( 2 ) ( 4 ) x + 1 = 8 x = 9

C h e c k : 4 ( 9 ) + 1 3 ( 9 ) = 8 Is this correct? 36 + 1 + 27 = 8 Is this correct? 8 = 8 Yes, this is correct .

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Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
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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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