# Solve an algebra equation for me? **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2011, 11:28pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016 "2011-04-19T23:28:01Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Incensed](https://avatars.discourse-cdn.com/v4/letter/i/eb8c5e/32.png) [@Incensed](https://boards.straightdope.com/u/Incensed)\ **Post date:** [April 19, 2011, 11:28pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/1 "2011-04-19T23:28:01Z")
So I’ve come to this- (abx)/(abx+c)=d/e -and I need to solve for “x” and I’m stumped. Sure I could look it up and figure it out, but then what would you guys do? ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [April 19, 2011, 11:35pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/2 "2011-04-19T23:35:02Z")
(abx)/(abx+c)=d/e abx\*e = (abx+c)\*d abex = abdx + cd abex - abdx = cd x(abe-abd) = cd x = cd / (abe-abd) ---
**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\ **Post date:** [April 19, 2011, 11:45pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/3 "2011-04-19T23:45:17Z")
nice going. i would have done step 2 in two phases. dunno, i’m slow when it comes to transposition. ---
**Author:** ![Incensed](https://avatars.discourse-cdn.com/v4/letter/i/eb8c5e/32.png) [@Incensed](https://boards.straightdope.com/u/Incensed)\ **Post date:** [April 19, 2011, 11:47pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/4 "2011-04-19T23:47:05Z")
I’ll sing your praises into perpuity, **The Hamster King**. Also, I’m an idiot for not seeing that. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [April 20, 2011, 3:12am UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/5 "2011-04-20T03:12:39Z")
Key #1: cross multiply to get rid of those nasty denominators. Key #2: get all the terms containing your desired variable grouped on one side, such that you can factor it out of them all. Divide out the terms left over, and you’re done. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [April 20, 2011, 6:32am UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/6 "2011-04-20T06:32:40Z")
Is it weird that I would go one step further and change it to x=ab(e-d)? I always try to limit repeated variables, as they add the chance for errors in the substitution process. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [April 20, 2011, 6:16pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/7 "2011-04-20T18:16:45Z")
It’s worth mentioning that Wolfram Alpha is great for this sort of thing. Here’s a [step-by-step](http://www.wolframalpha.com/input/?i=solve+%28a*b*x%29%2F%28a*b*x+%2B+c%29+%3D+d%2Fe+for+x) solution of your problem. ---
**Author:** ![sich\_hinaufwinden](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@sich\_hinaufwinden](https://boards.straightdope.com/u/sich_hinaufwinden)\ **Post date:** [April 20, 2011, 7:46pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/8 "2011-04-20T19:46:55Z")
> [@BigT](#): > > Is it weird that I would go one step further and change it to x=ab(e-d)? I always try to limit repeated variables, as they add the chance for errors in the substitution process. It’s kinda weird that the numerator disappeared and the denominator moved up top. Unless I’m missing something myself. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [April 20, 2011, 9:18pm UTC](https://boards.straightdope.com/t/solve-an-algebra-equation-for-me/579016/9 "2011-04-20T21:18:48Z")
> [@sich\_hinaufwinden](#): > > It’s kinda weird that the numerator disappeared and the denominator moved up top. Unless I’m missing something myself. No. I just forgot to type the numerator.