LisaNY Posted May 10, 2008 Share Posted May 10, 2008 I have been going over some basic Algebra topics with my dd before we move over to our Algebra 1 text. I have been using a variety of resources, just to see how different texts approach the same topic. We came across this problem in Dolciani: (I will use [] to indicate absolute value) "Explain why the following statement is true." If a is a real number, then [a] = a if a is zero or a positive number [a] = -a if a is a negative number It appears that the second condition is telling us that the absolute value of -a is negative a, but I know it is not *really* saying that. Can our resident math experts unfreeze my brain for me, please? Quote Link to comment Share on other sites More sharing options...
kathleen Posted May 10, 2008 Share Posted May 10, 2008 If you substitute the phrase "opposite of" for the negative sign, maybe it will make sense. So, if the number inside the absolute value sign is a negative number, then the absolute value is the opposite of that negative number (in other words, a positive number). |-3| = -(-3), or 3. Quote Link to comment Share on other sites More sharing options...
LisaNY Posted May 11, 2008 Author Share Posted May 11, 2008 If you substitute the phrase "opposite of" for the negative sign, maybe it will make sense. So, if the number inside the absolute value sign is a negative number, then the absolute value is the opposite of that negative number (in other words, a positive number). |-3| = -(-3), or 3. Thank you, Kathleen. That what what I was *thinking* they might be saying, but I wasn't sure. :001_smile: Quote Link to comment Share on other sites More sharing options...
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