Solving a system of equations.[br][br]For video on this topic see[br][url]https://www.khanacademy.org/math/algebra/systems-of-eq-and-ineq/fast-systems-of-equations/v/solving-linear-systems-by-substitution[/url][br]or [url]http://patrickjmt.com/solving-a-linear-system-of-equations-by-graphing/[/url][br]or [url]http://patrickjmt.com/solving-a-linear-system-of-equations-using-substitution/[/url][br]or[url] http://patrickjmt.com/solving-a-linear-system-of-equations-using-elimination-by-addition/[/url]