Question 806736
|-3r|=9 
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Absolute value is the magnitude, or the distance from zero.
For this one, either
(-3r) = 9
or
-(-3r) = 9
There are 2 cases, so you get 2 answers.
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You can use = 9 or = -9, but be careful when it's an inequality.
Changing the sign of the values inside the ABS | |  always works.