x2>4x

2x>4x 2x-4x>0 -2x>0 : (-2) x>0

x2>4x x2-4x>0 x(x-4)>0 x=0 v x-4=0 x=0 v x=4 rysujemy parabole ramionami do gory x∈(-∞,0) u (4,∞)