multiplication of algebraic expressions.
I searched Google under the key words "multiplication 'algebraic expressions'" to get these possible sources:
http://www.intmath.com/Basic-algebra/2_Multiplication-algebra.php
http://cstl.syr.edu/FIPSE/Algebra/Unit2/multiply.htm
(Broken Link Removed)
http://library.thinkquest.org/20991/alg2/frace.html#mult
http://www.wisc-online.com/objects/index_tj.asp?objID=GEM1904
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.