Just about anybody can solve two equations in two unknowns by somehow manipulating the equations. In this chapter, we will develop a systematic way for finding the solution, simply by checking the underlying geometry. This approach will later enable us to solve much larger systems of equations. Figure 5.1 illustrates repeatedly, the intersection of two lines: a problem that can be formulated as a 2 × 2 linear system. Intersections of lines: two families of lines are shown; the intersections of corresponding line pairs are marked. For each intersection, a 2 × 2 linear system has to be solved.