If |r+s|=|r-s|, then r*s must be equal to:	Choose the correct answer
A) -2  B) 2  C) 0  D) -3  E) 3
Solution 1: Distance perspective   |r-s| = |r+s| ==&gt; The distance of r and s is equal to the distance of r and -s.   &lt;=======(-s)=======0=======(s)======&gt;   Only 0 is the value that has a distance equal to s and -s.   Solution 2:   |r-s| = |r+s| (square both)   r^2 -2rs + s^2 = r^2 + 2rs + s^2   4rs = 0   rs = 0   Answer: 0
<result>C</result>
If |r+s|=|r-s|, then r*s must be equal to: