Given the quadratic function shown below whose turning point
     Given the quadratic function shown below whose turning point is (2, -4), which of the following gives the domain interval over which this function is decreasing?  x > -4  x  2  x  
  
  Solution
decreasing means when graph goes down
we can clearly see that it hapens on left side of x=2
hence choice (4) x<2 is correct

