## Elementary Linear Algebra 7th Edition

All of these equations determine a line in $xy$ plane. a) If there is exactly one solution that means that all of the three lines intersect at one unique point. The value of $x$ and $y$ at that point are the solution to the system (Graph on the left). b) This means that all of the three lines are the same and all points on that one line are the solutions to the system (Graph in the middle). c) This means that the three lines have no common intersection point. They may be parallel to each other or each two may intersect in the different points . This means than no $x$ and $y$ can simultaneously satisfy all three equations and thus the system has no solution (Graph on the right).