4 4 1 3 4 5 SolutionSolution Look for values of x for which
     4 -4 -1 -3 -4 -5  
  
  Solution
Solution:
Look for values of x for which there\'s y exists.
=> x (-,-1) U [2,)
Look for values of y for which there\'s x exists.
=> y (-,0) U [2,)

