# Thread: Need help with this fraction....

1. ## Need help with this fraction....

I don't know how to solve this fraction for n

19.6/(n^2-2n) = .16

2. Hello,

How do you want it to be solve ? There is no equation...

3. solve for n, sorry

4. In general, an equation is like this :

...... = ......

Two parts, an equal sign... :/

5. sorry didn't realize i typed the equation wrong

6. No. What Moo was saying you need an equal sign to actually solve something. For example, n + 5 = 9 so n = 4. But if you have just n + 5, you can't solve for anything.

Are you sure you typed it up correctly?

And also, you might want to watch your language. If you're expecting help, not the best idea to insult the person helping you.

7. yeah i just realized that Moo i'm sorry. its been a long long day

$\displaystyle \frac{19.6}{n^2-2n}=.16$

$\displaystyle 19.6=.16(n^2-2n)$

$\displaystyle .16n^2-.32n-19.6=0$

Do you know things about discriminant ?

9. $\displaystyle \frac{19.6}{n^{2} - 2n} = .16$

Multiply both sides by $\displaystyle n^{2} - 2n$:
$\displaystyle 19.6 = .16\left(n^{2} - 2n\right)$

Divide both sides by .16:
$\displaystyle 122.5 = n^{2} - 2n$

Move everything to one side to get a quadratic:
$\displaystyle 0 = n^{2} - 2n - 122.5$

Now solve for n using the quadratic formula:
$\displaystyle n = \frac{-(-2) \pm \sqrt{\left(-2\right)^{2} - 4(1)(-122.5)}}{2(1)}$

Make sure you check your solutions to see if they actually are solutions to your original equation and are not erroneous ones or ones that will result in divisions of 0.