(3/(а-3а^1/2)-а^3/2/(а^2-9а)):а^1/2/(а^1/2+3)=
((3*(а+3а^1/2)-а^3/2)/(а-3а^1/2)(а+3а^1/2))*(а^1/2+3)/а^1/2= ((3а+9а^1/2-а*а^1/2)(а^1/2+3))/(а^1/2(а-3а^1/2)(а+3а^1/2))=
(а^1/2(3а^1/2+9-а)(а^1/2+3))/(а^1/2(а^2-9а))=
(3а+9а^1/2-а*а^1/2+9а^1/2+27-3а)/(а^2-9а)=
(18а^1/2-а*а^1/2+27)/(а^2-9а).