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.
Solve system, A + 2B + 2C = 0, -4A - 18B + 2C = 1, -21A + 28B - 12C = 1
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random