пусть t=x-3
x-4=t-1; x-2=t+1; ((x-2)(x-4))^2+2(x-3)^2-2= ((t+1)(t-1))^2+2t^2-2=
=((t^2-1))^2+2t^2-2=t^4 -2t^2+1+2t^2-2=t^4-1
t^4-1=0
t=-1; t=1
x=2; x=4
