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.
det{{-1-t,3,-7},{0,2-t,-1},{1,-1,4-t}}
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random