Instructional Video7:00
Khan Academy

Systems of Three Variables 2, Systems of Equations and Inequalities, Algebra II

10th - 12th
Sal uses the elimination method to simplify a system of three variables. Next, he employs the substitution method to check his solution. This resource would nicely complement any lesson on this topic.
Instructional Video5:19
Khan Academy

Graphical Systems Application Problem, Systems of equations

9th - 11th
Sal evaluates a word problem and then solves it by graphing systems of equations. This problem would be significant as a daily challenge, as a concept review, or as a homework assignment. Show this video only after the students have had...