**Graphs of Linear Systems in Three Variables**

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**a.** The three planes may meet at a single, common point that is the solution of the system. See Figure (a).

**b.** The three planes may have the points of a line in common so that the infinite set of points that satisfy the equation of the line is the solution of the system. See Figure (b).

c. The three planes may coincide so that the solution of the system is the set of all points on a plane. See Figure (c).

d. The planes may have no points common to all three so that there is no solution of the system. See Figures (d), (e), and (f ).