Whenever I teach multivariable calculus I find students really struggle with both finding critical points and the method of Lagrange multipliers. I think that the reason is the same: solving systems of polynomial equations requires different tactics and much more care than solving one variable polynomials, or linear systems. As far as I know, the students have no practice until they see it in the calculus context and even worse none of the books that I've seen even mention it.
Are there any books/resources/modules that deal with solving systems of polynomial equations?
I would also be interested in anyone who teaches algebra/precalculus weighing on if/how solving systems of polynomial equations is presented.