algebra questions

dre954 · #1 $Old$ November 4th, 2009, 02:11 PM

Hello looking for some help recently wrote a test and it had questions something like this on it.

-3m (-1)
-1 = -1

I am just wondering what kind of algebra it was or even if you can help me solve a problem like this it would be a extremely huge help. Thanks

reiward · #2 $Old$ November 4th, 2009, 02:15 PM

Are you sure with that? A fraction with -1 = -1 as denominator? I don't think that's possible for an equation.

Bacterius · #3 $Old$ November 4th, 2009, 11:38 PM

Nah, that doesn't make any sense. Did you mean :

$\frac{\ {-3m}(-1)}{-1} = -1$

That is easy to solve, it is basic algebra.

dre954 · #4 $Old$ November 5th, 2009, 06:07 AM

Sorry I don't remember the question exactly I was just throwing something out there. I am not very good in math so this is not to basic for me.

What do you have to do to solve this equation do you have to break down the left side before it will look like a normal algebra question. After that I am OK

Raoh · #5 $Old$ November 5th, 2009, 06:37 AM

hi

"dre954"
if the question was like what "Becterius" wrote , $\frac{-3m(-1)}{-1}=-1$ ,how would u solve for $m$ ?

dre954 · #6 $Old$ November 5th, 2009, 08:17 AM

It is not the questions at hand that I care about I am wondering in what order do you use to solve a question like those ones.
I don't even know where to start with a question like that.

Thanks

Raoh · #7 $Old$ November 5th, 2009, 08:32 AM

you should know how to solve equations with one variable.

Defunkt · #8 $Old$ November 5th, 2009, 10:24 AM

Quote:

Originally Posted by Raoh $View Post$

you should know how to solve equations with one variable.

That's what he is asking help for, though... so I think we should help him instead of say that he should know it

$\frac{-3m(-1)}{-1} = -1$

We can see that both the numerator and the denominator have a factor of -1 in them, so we can reduce it to get:

$\frac{-3m}{1} = -1 \Rightarrow -3m = -1$

Now, we want to isolate m (we're looking for a value of m that makes the equation true), so we divide by -3, which is the coefficient of m, and get:

$m = \frac{-1}{-3} = \frac{1}{3} \Rightarrow \boxed{m=\frac{1}{3}}$

Bacterius · #9 $Old$ November 5th, 2009, 11:41 AM

You sure about your solution ? I thought it was :

$\frac{\ {-3m}(-1)}{-1} = -1$

$\frac{\ 3m}{-1} = -1$

$\frac{\ {-3m}}{1} = -1$

$\frac{\ {3m}}{1} = 1$

$3m = 1$

$m = \frac{\ 1}{3}$

You made a mistake by multiplying the top member of the fraction, and by dividing m by 3 (inattention I guess).

Defunkt · #10 $Old$ November 5th, 2009, 11:46 AM

Quote:

Originally Posted by Bacterius $View Post$

You sure about your solution ? I thought it was :

$\frac{\ {-3m}(-1)}{-1} = -1$

$\frac{\ 3m}{-1} = -1$

$\frac{\ {-3m}}{1} = -1$

$\frac{\ {3m}}{1} = 1$

$3m = 1$

$m = \frac{\ 1}{3}$

You made a mistake by multiplying the top member of the fraction, and by dividing m by 3 (inattention I guess).

$\frac{-1}{-3} = 3$ , obviously! :P

Bacterius · #11 $Old$ November 5th, 2009, 11:54 AM

Um ... no :

$\frac{\ {-1}}{-3} = \frac{\ {1}}{3}$

You must be confused with the reciprocals and the opposite.

dre954 · #12 $Old$ November 5th, 2009, 12:24 PM

thank you very much defunkt makes a little bit more sense now.

Defunkt · #13 $Old$ November 5th, 2009, 12:28 PM

Quote:

Originally Posted by Bacterius $View Post$

Um ... no :

$\frac{\ {-1}}{-3} = \frac{\ {1}}{3}$

You must be confused with the reciprocals and the opposite.

I was joking

In my initial post I wrote $...=\frac{-1}{-3}=3$ which is obviously wrong... :P

HallsofIvy · #14 $Old$ November 6th, 2009, 04:37 AM

Quote:

Originally Posted by dre954 $View Post$

Hello looking for some help recently wrote a test and it had questions something like this on it.

-3m (-1)
-1 = -1

I am just wondering what kind of algebra it was or even if you can help me solve a problem like this it would be a extremely huge help. Thanks

I would interpret this as $\frac{-3m}{-1}= \frac{-1}{-1}$ of course, that simply reduces to [math]\frac{3m}{1}= 1[math] so it is really 3m= 1. Divide both sides of the equation by 3 to solve for m.