7.1 Solving Systems of Equations by Graphing In this chapter we want to take a look at what happens when we put two linear equations, which we talked about in chapter 6, into a single problem. This gives us something called a system of equations. The first thing that we need to do is get a grip on the definitions. Example 1: a. Solve Applications of Systems of Equations by Substitution . We’ll copy here the problem solving strategy we used in the Solving Systems of Equations by Graphing section for solving systems of equations. Now that we know how to solve systems by substitution, that’s what we’ll do in Step 5.