Check please??
1. Can it ever be true that |a| = -a for real number a? Explain.
my answer: yes, if a

Question

Check please??
1. Can it ever be true that |a| = -a for real number a? Explain.
my answer: yes, if a < 0.
2. is it possible for a real number to be both rational and irrational? Explain.
my answer: no, b/c rational #s can be written as a fraction and irrational #s cannot.
Thank you!

phi · Answer

I think |0|= -0,  so how about a≤0  ?

mathstudent55 · Answer

2. is correct.

anonymous · Answer

okay, thanks! but my book said for #1 yes, |a| = -a if a < 0.

mathstudent55 · Answer

For 1. I agree with @phi, not with your book.

anonymous · Answer

okay, thank you both! :)

phi · Answer

Interesting. Wolfram says otherwise http://www.wolframalpha.com/input/?i=for+real+x%2C++solve+%7Cx%7C+%3D+-x

mathstudent55 · Answer

wlcm