Algebra.help
http://www.algebrahelp.com/worksheets/view/graphing/slopeintercept.quiz
Algebra-Trig (Bruner Math)
http://www.brunnermath.com/algebraiiiandtrig.htm
Graphing Linear Equations Focus is algebra 1 content — lessons, puzzles, etc.
http://www.terragon.com/tkobrien/algebra/
Graphing Linear Equations
http://www.math.com/practice/Algebra.html
Interactive Mathematics Activities High school mathematics activities that can be done online
http://www.cut-the-knot.com/Curriculum/index.shtml
Mr. Hoffman's Math Page Lots of worksheets and answers for grades 9-12.
http://www.pembroke.k12.ny.us/hs/teachers/HofmanM/hofmanm.html
Visual Math Learning Lessons and Games
http://www.visualmathlearning.com/
Webmath Help with problems in Pre-algebra, algebra, geometry, trigonometry, calculus, data analysis and real world mathematics.
http://www.webmath.com/
Word Problems Solving linear equations
http://www.sci.wsu.edu/~kentler/Fall97_101/nojs/Chapter2/section3.html