If y=x5-4x4+4x3=x3(x2-4x+4)=x3(x-2)2=0, then:
y'=5x4-16x3+12x2=0=x2(5x2-16x+12)=x2(5x-6)(x-2)⇒x=0, x=6/5, x=2 (x coord of stationary points).
When x=0 or 2, y=0; x=6/5, y=(216/125)(-⅘)2=3456/3125=1.10592.
The question isn't clear so I'm guessing: y=(?)(?)=x3(x-2)2=0 and the stationary points are when x=0, 2, 6/5, stationary points at (0,0), (2,0) and (6/5,3456/3125).