Linear algebra

Given 3 simultaneous equations with 3 unknowns each, how do i determine if they have 0, 1, or infinite sets of solutions? I know how to convert the equations into reduced echelon form, if it helps. Thanks.

>>6
How is that so complicated? The three axis changing over another axis, and the change in that over another axis. I had to construct 5 dimensional cross sections for my introductory physics class.