Solve Systems
Solve Systems
http://www.quia.com/rr/59310.html

http://www.quia.com/cb/79607.html

http://www.coolmath.com/algebra/12-2x2-systems-of-equations/
http://www.crctlessons.com/systems-of-equations-game.html
http://www.superteachertools.com/jeopardy/usergames/Jan201003/game1263916458.php 
(scrolldown for problems)
(word problems challenge site)
Video Substitutionhttp://www.onlinemathlearning.com/solving-systems-of-equations-3.html