quadratic fit((77,89.9), (5000,84.5), (15000,74.25), (25000,65), (40000,53), (55000,43.25), (70000,36))

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.