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.
40 - 2 * sqrt(15) * 5 * sqrt(15)/4
40 - 2 * sqrt(15) * 5 * sqrt(15)/4
Natural Language
Math Input
Extended Keyboard