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Variables

Page history last edited by PBworks 16 years, 4 months ago

 

 

VARIABLES

 

 

 

 

What is a variable?

 

A variable is a symbol that represents an unknown number.

 

What a variable means in an equation.

 

Example: 2x

2x means whatever number that x represents, you multiply it by 2.

 

How do you solve a

 

linear equation? 

 

 

Additon:

 

Example: 2+x= 24

Subtract 2 on both sides of the equation. 2-2+x= 24-2

Now you are left with your answer. x=22

Check your answer by putting your answer back into the equation. 2+22=24

 

Subtraction:

 

Example: x-2=24

Add 2 on both sides of the equation. x-2+2=24+2

Now you are left with x=26.

Check your answer by putting it back into the equation.  26-2=24

(In the equation x-2=24, the 2 is negative. To change it back into a positive, you would have to add positive 2.)

 

Multiplication:

 

 

Divide 2 on both sides of the equation. 2x/2= 24/2

Now you are left with x= 12

Check your answer by putting it back into the equation. 2x12=24

 

Division:

 

Example: x/2=24

Mulitply 2 on both sides of the equation. x/2*2=24*2

Now you are left with x= 48

Check your answer by putting it back into the equation. 48/2=24

 

How do you solve a two step equation?

 

 

 

Example: 5x+25=50

Subtract 25 on both sides of the equation. 5x+25-25=50-25

Now you are left with a one step equation. 5x=25

Divide 5 on both sides of the equation. 5x/5=25/5

Now you are left with x=5.

 

What if there is a fraction in the equation?

 

Example: 1/2x - 4 = 24

Add 4 on both sides of the equation. 1/2x-4+4=24+4

Now you are left with a one step equation. 1/2x=28

Multiply the reciprocal of 1/2 on both sides. 2*1/2x = 28*2

Now you are left with x= 56.

 

 

How to combine like terms.

 

Example: 2x+x=3.

Comebine like terms, add the x's together. 3x=3

Divide 3 on both sides of the equation. 3x/3=3/3

Now you are left with x=1.

 

Example: 2x+3x=5

Combine Like terms, add 2x to 3x. 5x=5

Divide 5 on both sides. 5x/5=5/5

Now you are left with x=1.

 

How to solve an equation with variables on both sides.

 

Example: 2x+3=4x+2

Subtract the smaller amount of x's from the larger amount of x's, subtract 2x on both sides. 2x-2x+3=4x-2x+2

Now you have variables on one side. 3=2x+2

Subtract 2 on both sides of the equation. 3-2=2x+2-2 

Now Divide 2 on both sides of the equation. 1/2=2x/2

Now you are left with 1/2=x.

 

Links

 

For more information about Combing Like Terms Visit: http://taylormath.pbwiki.com/Like+Terms 

For more information about multiplying fractions visit: http://taylormath.pbwiki.com/Multiplying+Fractions

 

Some Links I Used To Make This Page:

 

http://library.thinkquest.org/20991/alg/eq.html

 

 

 

 

 

 

 

 

 

 

Comments (23)

Anonymous said

at 9:04 am on Oct 29, 2007

wow i love the colors and it a grate page

Anonymous said

at 12:25 pm on Oct 29, 2007

You have good definations

Anonymous said

at 8:31 pm on Oct 29, 2007

Nice page~!!! You have great organizational skills. The highlighter-green color is somewhat hard to see though. Otherwise, it is very 1337. Llamas FTW ^___^<3

Anonymous said

at 8:50 pm on Oct 29, 2007

nice.
i love the blue & green.

Alex L. said

at 7:34 pm on Oct 30, 2007

Great colors u picked

Anonymous said

at 9:46 am on Nov 5, 2007

woahh!! so colorful O___O
but, you should put up pictures tho :O

Anonymous said

at 10:00 am on Nov 5, 2007

the green is blinding! pictures would be good :]

Anonymous said

at 10:04 am on Nov 5, 2007

nice page =) you might wanna add some pictures. and the green burns my eyes.

Anonymous said

at 10:06 am on Nov 5, 2007

lol everyone hates the green color =P.

Anonymous said

at 10:08 am on Nov 5, 2007

heyy nenette i like ur page and i don't think that yu should take the greeen down cuz it looks fine..
everything looks good to me...

Anonymous said

at 10:14 am on Nov 5, 2007

TYVM Sherry =D <333333333333333333333333333 lol

Anonymous said

at 10:19 am on Nov 5, 2007

T_T u commented on mai page and said "Manya~~ i love ur page!!!!!" -_- im not manya!

Anonymous said

at 1:09 pm on Nov 5, 2007

great page ,,add some pics tho

Anonymous said

at 2:32 pm on Nov 5, 2007

the highlighter green color is looking a bit weird, oterwise, nice

Anonymous said

at 2:34 pm on Nov 5, 2007

I like your page. The one thing that bothered me, mostly, was how bright the green text was. I say this since it was hard to read, and I think I just went from 20/20 vision to 20/15 vision.

Anonymous said

at 2:51 pm on Nov 5, 2007

i love your page... the color is very noticiable.....add some pictures......who diesn't like pictures..

Anonymous said

at 2:53 pm on Nov 5, 2007

i like the page because the colors are really bright &get my attention. butttt they're a litttle TOO bright. other than that, it's cool.

Anonymous said

at 7:46 pm on Nov 5, 2007

I like the colors a lot! The picture is very nice too. It's deserves to be explained a little...

Anonymous said

at 8:53 pm on Nov 5, 2007

Nice! Still, could you please explain how variables are used in real life? It would be llamalike. ~~ ^__^

Anonymous said

at 10:14 am on Nov 13, 2007

hi nenette i love the colors you use pink and blue cool

Anonymous said

at 9:06 pm on Nov 14, 2007

yes it's ok

Anonymous said

at 7:52 pm on Nov 15, 2007

nenette is it ok if i use your page as a link also

Anonymous said

at 11:18 pm on Nov 21, 2007

Why do we use variables? What symbols are OK to use as variables? How are variables different than unknowns or constants? There are lots of thisngs you could tell us about variables, rather than telling us how to solve equations.
2.5 of 4 points
9.5 of 12 total project points

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