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.
z = 1.3907 - 0.087591x -0.25811y + 0.033397xy + 0.0027985x^2 + 0.00089385y^2
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
