Can Mathcad (or one of the extensio

Dear Fabcio, the meaning of Eigen is characteristic, and the
equation you have provided is quadratic with a well known
solutions, x= (-B +/-Sqrt(B^2 - 4*A*C))/(2*A). The equation
you have provided is "the characteristic equation" of your
model which for instance could represent "two masses
connected by a spring". The eigenvalues are the roots of the
given characteristic equation you provided which happens to
be quadratic. The two eigenvectors are the two (mode) shapes
of the "two-masses & a spring" model I just mentioned above.

MathCAD can solve for this equation symbolically using the
solver-block as Find(x) --->

You may want to elaborate more on your question to get
to your most specific needs.

Sincerely,

MatheMagician