Curated OER
Example and Steps to Solving Linear Systems Using Substitution
In this linear equation activity, students solve five systems of linear equations using the substitution method. Three examples with steps to solve are provided.
National Council of Teachers of Mathematics
Nctm: Illuminations: Resources for Teaching Math: Algebra Tiles
Try this hands-on approach to solving algebra problems with this interactive website. Students are able to "solve equations, substitute in variable expressions, expand, and factor".