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.
7 \cdot (\frac{1}{1-(-\frac{64}{343})} - \frac{1-(-\frac{64}{343})^3}{1-(-\frac{64}{343})})
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random