The Quadratic Equation Solver posted on this page solves for both real and imaginary (if applicable) results. Also on this site: solvers for the Cubic and Quartic equations, N Equations in N Unknowns, Eigenvalues and Eigenvectors, Cubic Spline Interpolation, Numerical Integration, and Least-Squares Data-Fitting.

Maths information about mathematical factoring, number factors and how to factor numbers.