Factor[Resultant[(a^3 - 3a b^2)s^3 - 58, (3a^2b - b^3)s^3 - 145, b]]

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.