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.
abs(x+y) + abs(x-y) = 9
abs(x+y) + abs(x-y) = 9
Natural Language
Math Input
Extended Keyboard