Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
(1000/x)-(1000/(x-120)) = 1/2
(1000/x)-(1000/(x-120)) = 1/2
Natural Language
Math Input
Extended Keyboard
