# Math Help - Newcomer - Algebra and fraction help.

1. ## Newcomer - Algebra and fraction help.

Hello, Im new to this forum and I need a little help with Algebra/fraction. English is not my mother language, so I may confuse some math descriptions.

Here's my problem:

$
8xy-16x/4xy-8x
$

I still need to fix some problems. That is a fraction with algebra.

2. Originally Posted by Pingu
Hello, Im new to this forum and I need a little help with Algebra/fraction. English is not my mother language, so I may confuse some math descriptions.

Here's my problem:

$
8xy-16x/4xy-8x
$

I still need to fix some problems. That is a fraction with algebra.
If you take out a factor of 2 on the top, then you can write the fraction as:

$\frac{2(4xy-8x)}{4xy-8x}$

Can you see what cancels>?

3. Originally Posted by Pingu
Hello, Im new to this forum and I need a little help with Algebra/fraction. English is not my mother language, so I may confuse some math descriptions.

Here's my problem:

$
8xy-16x/4xy-8x
$

I still need to fix some problems. That is a fraction with algebra.
Hello Pingu,

I'm going to take a guess that this is your expression:

$\frac{8xy-16x}{4xy-8x}$

In the numerator, factor out the common factors of 8x.

In the denominator, factor out the common factors 4x/

$\frac{8x(y-2)}{4x(y-2)}$

Do you think you can finish up?

Edit: Mush beat me again as usual, but I factored the thing a bit differently, so I'll leave it. Dang you Mush!

4. Mush and masters: Thanks guys That was just what I needed, but I still need to figure out this MATH code. The fraction was almost as the one I made, but it had "x´3" and the likes. I will get back, when I get better math coding skills

EDIT: So, Im back, hehe. This was the original fraction I had problems with:

$\frac{8x^3y-16x^2}{4x^2y-8x}$

5. Originally Posted by Pingu
Mush and masters: Thanks guys That was just what I needed, but I still need to figure out this MATH code. The fraction was almost as the one I made, but it had "x´3" and the likes. I will get back, when I get better math coding skills
Do you mean $x^{2}$.

If you click on the equations in other people's posts, you can see the code for various things:

Fractions:

$\frac{a}{b}$

6. Originally Posted by Mush
Do you mean $x^{2}$.

If you click on the equations in other people's posts, you can see the code for various things:

Fractions:

$\frac{a}{b}$
Yes, $x^{2}$. It was just the ^ I could not find. I have a wierd letter in Faroese (Ð) instead of ^.

Here is another one I had problems with in school today:

$
\frac{2x-4}{3x^2-12}
$

If I short it a bit, here is what it comes down to:

$
\frac{2(x-2)}{3(x^2-4)}
$

Then:

$
\frac{2(-2)}{3(x-2)}
$

And the result?

$
\frac{2}{3x}
$

Correct?

7. Originally Posted by Pingu
Yes, $x^{2}$. It was just the ^ I could not find. I have a wierd letter in Faroese (Ð) instead of ^.

Here is another one I had problems with in school today:

$
\frac{2x-4}{3x^2-12}
$

If I short it a bit, here is what it comes down to:

$
\frac{2(x-2)}{3(x^2-4)}
$

Then:

$
\frac{2(-2)}{3(x-2)}
$

And the result?

$
\frac{2}{3x}
$

Correct?
Not quite!

$
\frac{2(x-2)}{3(x^2-4)}
$

This is correct. And from here you should realise that the denominator contains a difference of two squares, and can be written:

$
\frac{2(x-2)}{3(x^2-2^2)}
$

$
=\frac{2(x-2)}{3(x+2)(x-2)}
$

Then the (x-2) cancels on the top and bottom, leaving:

$
\frac{2}{3(x+2)}
$

8. Originally Posted by Pingu
Yes, $x^{2}$. It was just the ^ I could not find. I have a wierd letter in Faroese (Ð) instead of ^.

Here is another one I had problems with in school today:

$
\frac{2x-4}{3x^2-12}
$

If I short it a bit, here is what it comes down to:

$
\frac{2(x-2)}{3(x^2-4)}
$

Then:

$
\frac{2(-2)}{3(x-2)}
$

And the result?

$
\frac{2}{3x}
$

Correct?
Pingu,
Actually usually in such algebraic manipulation problems, its usually easy to figure out if you are wrong. Just substitute a few values for x and check whether both sides of the equations are valid.

If you are wrong you can try working on the problem again. This method is usually very helpful since you can do it yourself