SOLUTION: I've solved {{{ sqrt( z^2+8z+16 ) }}} but I need help getting a better understanding about why/when you put absolute value signs. Can you please help? Thanks!

Algebra ->  Square-cubic-other-roots -> SOLUTION: I've solved {{{ sqrt( z^2+8z+16 ) }}} but I need help getting a better understanding about why/when you put absolute value signs. Can you please help? Thanks!      Log On


   

Question 552673: I've solved +sqrt%28+z%5E2%2B8z%2B16+%29+ but I need help getting a better understanding about why/when you put absolute value signs. Can you please help? Thanks!
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Recall that the square root of a quantity always gives two answers, a positive answer and a negative answer.
If you want to indicate that only yhe positive answer applies, then you would us the absolute value sign.
Example, to indicate that only the positive answer applies:
sqrt%28x%5E2%29+=+abs%28x%29
In your problem:
sqrt%28z%5E2%2B8z%2B16%29+=+sqrt%28%28z%2B4%29%5E2%29=abs%28z%2B4%29