1) (решение исправлено)
(х/у+у/х+2)*1/(х+y)^2=(х^2+у^2+2xy)/(ху)*1/(х+y)^2=1/(xy) = 1/(корень(2*8)) = 1/4=0,25
2)
(x+1+1/(4*x))/(x-1/(4*x)) = (((x+1)*4x+1)/(4*x))/((4x-1)/(4*x)) = ((x+1)*4x+1)/(4x-1) =
((11,5+1)*4*11,5+1)/(4*11,5-1) =
12,8
3)
(x^6-1)*1/(x^3+1)*(x+1)/(x^2+x+1)=(x^3-1)*(x+1)/(x^2+x+1)=x^2-1=4*3-1=11
4)
(x*(x^2+3y^2)-y*(Y^2+3x^2))/ ((1/x)-(1/y)) = (x-y)^3*xy/ (y-x) =- (x-y)^2*xy =- (5*корень(2))^2*7*2*2=
-1400