When in the course of algebraic events, it becomes necessary for a student to finish their homework, and to solve a system of linear equations, a decent respect to the opinions of their math teacher requires that they should know multiple ways to find the solutions.
…Maybe that's a bit much? We don't want to declare a revolution or anything like that.
Anyway, a system of linear equations is just a set of two or more different linear equations. You'll occasionally be given two linear equations and asked to solve for x and y. We want to know all of the values for x and y that make both equations true. There are numerous ways to do this, including graphing the lines, using substitution, some clever elimination, and guessing.
Just kidding on that last one.