Sunday, October 21, 2012

Why do we sometimes flip the inequality symbols?



When an expression is multiplied or divided by a negative number its preference changes. For example, we have an inequality 8> 4. It means eight is greater than four. Now if we divide or multiply it by -1 it will become -8>-4. However this is incorrect as -4 is greater than -8. Therefore, we need to flip the inequality sign to make the expression mathematically true. So the correct expression is -8<-4, which is mathematically true.




     Citation (images): - http://www.studyzone.org/testprep/math4/d/numberlinel.cfm
                  -http://www.math.com/school/subject2/images/S2U3L4DP2.gif
               

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