Khan Academy
Khan Academy: Algebra: Adding Polynomials
Demonstrates how to add two given polynomials. One of the polynomials can be simplified before being added to the other polynomial. [2:10]
Art of Problem Solving
Art of Problem Solving: Simplifying Linear Expressions
Video tutorial uses examples to reinforce how to simplify linear expressions. [4:49]
Khan Academy
Khan Academy: Algebra: Adding and Subtracting Polynomials 2
Demonstrates how to subtract a trinomial from a binomial. [1:43]