The document discusses three methods for solving systems of linear equations: substitution, graphing, and elimination. The substitution method involves substituting one equation into the other to solve for the variables. The graphing method graphs both linear equations on the same plane and finds the point where they intersect. The elimination method eliminates one variable by adding or subtracting the equations to obtain zero for that variable, then solving for the other. The solution to a system of linear equations using any method is the point where the equations are equal.