http://education.yahoo.com/college/sattip SAT* Tip of the Day tutorial en-us Copyright (c) 2009 Yahoo! Inc. All rights reserved. Thu, 02 Jul 2009 17:00:00 GMT http://l.yimg.com/a/i/edu/masthead/mastlogosmall2.gif http://education.yahoo.com/ 144 17 http://education.yahoo.com/college/sattip/ Math questions involving two equations and two unknowns can usually be combined into one equation with one unknown. college/sattip/index?d=20090703 Thu, 02 Jul 2009 17:00:00 GMT