1/2x(x-2)=x²-4x+4
1/2x(x-2)=(x-2)²
x(x-2)=2(x-2)²
2(x-2)²-x(x-2)=0
(x-2)[2(x-2)-x]=0
(x-2)(x-4)=0
x1=2,x2=4