# Factoring [Solved!]

**Michael** 24 Nov 2015, 10:17

### My question

Your mathematics site is absolutely brilliant and so easy to navigate through your "sitemap". Hidden answers are excellent and the interactive applets make the site so dynamic also the aside information is super. It took a lot of effort to produce what you have achieved and I hope you have a good sponsor to compensate you for same so thanks very much for enjoyable maths.

I am still confused on that little problem i.e. `(x^2 - y^2)/(y - x)` in equivalent fractions. Let `x = 4` and `y = 3`

Then `(x^2 - y^2)/(y - x) = (16-9)/(-1) = -7`

But `(x^2 - y^2)/(x - y) = (16-9)/(1) = 7`, a difference of `14`.

Thank You Again,

### Relevant page

5. Equivalent Fractions

### What I've done so far

Struggled with the solution of Exercise 4 for some time

X

Your mathematics site is absolutely brilliant and so easy to navigate through your "sitemap". Hidden answers are excellent and the interactive applets make the site so dynamic also the aside information is super. It took a lot of effort to produce what you have achieved and I hope you have a good sponsor to compensate you for same so thanks very much for enjoyable maths.
I am still confused on that little problem i.e. `(x^2 - y^2)/(y - x)` in equivalent fractions. Let `x = 4` and `y = 3`
Then `(x^2 - y^2)/(y - x) = (16-9)/(-1) = -7`
But `(x^2 - y^2)/(x - y) = (16-9)/(1) = 7`, a difference of `14`.
Thank You Again,

Relevant page
<a href="/factoring-fractions/5-equivalent-fractions.php">5. Equivalent Fractions</a>
What I've done so far
Struggled with the solution of Exercise 4 for some time

## Re: Factoring

**Newton** 24 Nov 2015, 21:08

Sometimes these mental blocks can drive us crazy! While your substitutions are quite correct, what I have on the site is a negative on the denominator of the fraction in the second line.

Your first line is fine:

`\frac{x^2 - y^2}{y - x} = \frac{16-9}{-1} = -7`

But the second line should be

`\frac{x^2 - y^2}{-(x - y)} = \frac{16-9}{-1} = -7`

So they are the same.

Hope that makes sense.

X

Sometimes these mental blocks can drive us crazy! While your substitutions are quite correct, what I have on the site is a negative on the denominator of the fraction in the second line.
Your first line is fine:
`\frac{x^2 - y^2}{y - x} = \frac{16-9}{-1} = -7`
But the second line should be
`\frac{x^2 - y^2}{-(x - y)} = \frac{16-9}{-1} = -7`
So they are the same.
Hope that makes sense.

## Re: Factoring

**Michael** 25 Nov 2015, 16:15

I see it now. Thanks

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