1. Advanced Algebra 73
Bernabe, Julieta G., et al. Advanced Algebra Trigonometry and Statistics
Functional Approach Workbook. ©2004. Vabal Publishing House, Inc. p. 42 - 67
Dolciani, Mary P. et al. Algebra & Trigonometry: Structure and Method Book 2.
1997. Houghton Mifflin Company. Pp. 207 – 234.
Petilos, Gabino P. Simplified College Algebra. 2004. Trinitas Publishing Inc. Pp. 233
– 255.
Sorgenfrey, Robert H. et al. Algebra & Trigonometry: Structure and Method Book
2. 1990. Houghton Mifflin Company. Pp. 227 – 237.
http://www.freemathhelp.com/direct-variation.html
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http://users.stlcc.edu/amosher/MTH185RationalFunctions.htm
http://www.mathmotivation.com/lessons/properties-rational-functions.html
http://oregonstate.edu/instruct/mth251/cq/FieldGuide/rational/more.html