A linear sytem of equations in three variables , , has the form
The set of all solutions of such a system can be geometrically interpreted as the intersection of the three planes given by the system's equations. The following situations may occur:
Exactly one solution: The three planes concur at one point only.
No solution: The three planes have no common points.
Infinitely many solutions: All three planes concur at a line or coincide with each other.
Such a linear system can be solved by elimination of variables or by Gaussian transformation with subsequent back substitution, for instance.