A 2x2 system has two equations and two unknowns (x, y). A 3x3 system adds a third equation and a third unknown (z).
Cramer's rule uses determinants; Gaussian elimination uses row operations with back-substitution. Both give the same answer, and the steps panel switches to show whichever method you pick.
When the solution is a simple fraction (e.g. 3/2 rather than 1.5), display it in fraction form.