Represent constraints by equations or inequalities, and by systems of equations and/or inequalities, and interpret solutions as viable or nonviable options in a modeling context.
HSA.REI.C.5
Prove that, given a system of two equations in two variables, replacing one equation by the sum of that equation and a multiple of the other produces a system with the same solutions.
HSA.REI.C.6
Solve systems of linear equations exactly and approximately (e.g. With graphs), focusing on pairs of linear equations in two variables.
