((x-3)^2)^1/2=abs(x-3) so the question becomes is abs(x-3)=3-x, this is true if x-3<0 or x<3

A: quotes that x is not 3. this does not help you at all
B: quotes that -x*abs(x)>0. sice abs(x)>0 it follows that -x>0 or x<0. Since x<0 then the equation in question is true.