We square both sides:

  

  
  
  

  

  

We get 3, -3, 2, -2

But we must check for extraneous answers:

   
  
  
  

3 is not a solution


   
  
  
  

-3 is not a solution


   
  
  
  

2 is a solution


   
  
  
  

-2 is a solution

So there are only two solutions, 2 and -2.

Edwin