Math Is Fun Forum

blank_brunette

Member

Registered: 2008-03-27

Posts: 46

Equations? HELP!

hi...i have these equations that i am filling in for and finding out the replacements..now, i know how to do it, but i get confused  with the opposites, like this

x and y are opposites, like x=5 y= -5......or y=5 and x=-5

sooo, i have:

3(2y)-3y+4=2y+5 wat would y equal?
altho, that doesnt have a x, so here's another one

3x+15=2y

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In this world of cheerios, be a fruitloop! ♥

JohnnyReinB

Member

Registered: 2007-10-08

Posts: 453

Re: Equations? HELP!

The first one would be simple. Just simplify it.

3(2y)-3y+4=2y+5
   6y-3y+4 = 2y+5 
         3y+4=2y+5
           y+4=5
               y=1
               x=-1 (since they are opposites)

Last edited by JohnnyReinB (2008-05-19 01:44:50)

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"There is not a difference between an in-law and an outlaw, except maybe that an outlaw is wanted"

Nisi Quam Primum, Nequequam

SvenBee

Member

Registered: 2008-03-08

Posts: 106

Re: Equations? HELP!

For the second one just do the same thing as the first one:
2y=3x+15                                   2y=3x+15
y=(3x+15)/2                             3x=2y-15
                                                  x=(2y-15)/3

Last edited by SvenBee (2008-05-15 15:54:55)

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e...the red-headed stepchild of math.

JohnnyReinB

Member

Registered: 2007-10-08

Posts: 453

Re: Equations? HELP!

Oh, yeah, to solve an equation with two variables, you need two equations.
In this case, the two equations are:
3x+15=2y (given)
        x=-y (since x is the opposite of y)

Just place the value of x (-y) to the first equation:

3(-y) + 15 = 2y
  -3y + 15 = 2y
           15 = 5y
              3=y
             -3=x

Voila! all there is to it!

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"There is not a difference between an in-law and an outlaw, except maybe that an outlaw is wanted"

Nisi Quam Primum, Nequequam

blank_brunette

Member

Registered: 2008-03-27

Posts: 46

Re: Equations? HELP!

hello people...i am working on some make-up worksheets cuz i am on vacation, and its a little tricky since i have no idea what i am doing and i cant exactly call anyone for help..:)
anywayz, i am looking at some quadratic equations and i am determining the difference between them and that's all. But it seems too easy to just write down the difference between the parabola! Right? And I still have no idea what to do with the minimum/max. point..like, how to get it? please help  me!
h=16t^2+12t+0.2..........here is an equation...i have made a table and graphed it, but beyond that i am stuck ......help anyone?

i feel frustrated! lol

Last edited by blank_brunette (2008-05-23 00:31:11)

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In this world of cheerios, be a fruitloop! ♥

blank_brunette

Member

Registered: 2008-03-27

Posts: 46

Re: Equations? HELP!

I have been working on all of my make-up work for 3 hrs and its only 11:01!
Now on One of my problems it says to investigate the patterns of change in the y-values and to determine the changes in the pattern...like, for y=2x^2.....or.......1/2x^2...PLEASE HELP ME!!! IT LOOKS TO BE AN ALL NIGHTER FOR ME!!!!

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In this world of cheerios, be a fruitloop! ♥

blank_brunette

Member

Registered: 2008-03-27

Posts: 46

Re: Equations? HELP!

How can u tell when an equation is quadratic? I mean, i know that it has to have a quardratic term and everything, but what exactly is that? Like, is x^2-7 quadratic? how can u tel???????

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In this world of cheerios, be a fruitloop! ♥

JohnnyReinB

Member

Registered: 2007-10-08

Posts: 453

Re: Equations? HELP!

A quadratic equation is an equation in the form of

Where A, B, and C are numeric coefficients and

A≠0

Apart from that, i know nothing of quadratic equations. Sorry!

Last edited by JohnnyReinB (2008-05-29 17:37:31)

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"There is not a difference between an in-law and an outlaw, except maybe that an outlaw is wanted"

Nisi Quam Primum, Nequequam

blank_brunette

Member

Registered: 2008-03-27

Posts: 46

Re: Equations? HELP!

i already got the answers...i had to get the answers quick..lol thnx tho!

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In this world of cheerios, be a fruitloop! ♥