3) 0,6/(0,25x+0,5)-(0,2x+0,4)/(0,5x²+2x+2)+x/(x+2)=
=0,6/(0,25*(x+2))-(0,2*(x+2))/(0,5*(x²+4x+4)+x/(x+2)=
=2,4/(x+2)+0,4*(x+2)/(x+2)²+x/(x+1)=2,4/(x+2)-0,4/(x+2)+x/(x+2)=
=(x+2)/(x+2)=1.
4)((8m³-1)/(3m²-18v+27))*((m²-3m)/(8m²+4m+2)=
=(2m-1)*(4m²+2m+1)*m*(m-3)/((3(m²-6m+9)*2*(4m²+2m-1)=
=(2m-1)*m*(m-3)/(6*(m-3)²)=m*(2m-1)/(6*(m-3))=(2m²-m)/(6m-18).
5) (4/(x-y)-(√x+√y)/(x√y-y√x))/((√xy-x)/√y)=
=(4/((√x+√y)(√x-√y)-(√x+√y)/√xy(√x-√y))/(√x(√y-√x)/√y)=
=(4√xy-(√x+√y)²/(√xy(√x+√y)(√x-√y))/(-√x(√x-√y)/√y)=
=(4√xy-x-2√xy-y)*√y)/(√xy(√x+√y)(√x-√y)*(-√x*(√x-√y))=
=(-(√x-√y)²*√y)/(√xy(√x+√y)(√x-√y)²(-√x))=1/(x(√x+√y)).