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.
{{-1,2},{3,1}}.{{-1/7,2/7},{3/7,1/7}}
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random