<p>If xy=2, yz=5, xz=10, and x>0, then xyz=?</p>
<p>Answer 10</p>
<p>Please explain.</p>
<p>If x > 0, then y and z are also greater than 0, because xy = + and xz = +. If they were negative, then the product would also be negative.</p>
<p>So xy = 2 means (2)(1) = 2 or (1)(2) = 2. </p>
<p>Since yz = 5, y cannot be 2. It has to be 1. Therefore, x=2, y=1, and z=5. xz=10 confirms this: (2)(5)= 10.</p>
<p>xyz = 10 because (2)(1)(5) = 10</p>