How to quickly solve a quadratic equation

[MattH]

On my Casio scientific calculator I am able to quickly solve equations in the form of ax^3+bx^2+cx+d=0 (or with a degree of two) for x by simply entering the a,b,c, and d values in a table. I've done a decent amount of searching and the closest thing I've gotten is putting the equation into 'solve symbolic view', then pressing Num and setting y=0. That seems to only give me the positive x-intercept, though. Any suggestions?