sqrt(x-4)=t
x-4=t^2 ⇒ x=t^2+4
sqrt(x–4*sqrt(x–4))–sqrt(x+4*sqrt(x–4)) =sqrt(t^2+4–4t)–sqrt(t^2+4+4t)=sqrt((t-2)^2)-sqrt((t+2)^2)=
=|t-2|-|t+2|
При х=2008
t=sqrt (2008-4)=sqrt(2004) > 2
значит |t-2|=t-2
|t+2|=t+2
Тогда
sqrt(x–4*sqrt(x–4))–sqrt(x+4*sqrt(x–4)) =|t-2|-|t+2|=
=t-2-t-2=-4
О т в е т. -4.