The set of values of  x  for  which $x(x-2) (x-4) >0$is--------

x(x-2) (x-4)>0 Use wavy curve method 

If x less than zero all three factors are negative, between 0 and 2 , x is positive, other two are negative, total it is positive, between 2 and 4 first two are positive, third one negative, finally total is negative, more than 4 all are positive, so total equation is positive