{{1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 2, -2}, {0, 0, 1, 0}} . {{x}, {y}, {z}, {1}}

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.