Khan Academy
Khan Academy: Two Variable Inequalities Word Problems
Solve word problems that involve linear inequalities in two variables. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Texas A&M University
Wtamu Virtual Math Lab: College Algebra: Systems of Linear Equations
This tutorial will show you a four-step process for solving problems involving systems of linear equations. View several examples of Polya's process of problem solving and hone your own skills with practice exercises.