iFactor Quadratics app for iPhone and iPad
This is a simple application that will factor quadratic equations, if possible. Its quick, handy, and easy.
Example: 6x² + 13x + 6 = (2x+3)(3x+2).
If you need to *solve* quadratics as well as factor them, you should check out iFactor and Solve Quadratics in the app store. It can handle any quadratic, including ones with complex roots.