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.
[y=375,y=(15*(3*x+4))*x+15]x=-1/3 to 4
[y=375,y=(15*(3*x+4))*x+15]x=-1/3 to 4
Natural Language
Math Input
Extended Keyboard