hard question lol

Let's call the number  " n " .

 

The problem tells us that...

n * 2n  =  72

 

2n²  =  72              Divide both sides of this equation by  2  .

 

n²  =  36                Take the  ±  square root of both sides.

 

n  =  ±√36

 

n  =  ± 6

 

So..your number can be either  6  or  -6  .

 

Half of   6  is    3  .

Half of  -6  is  -3  .