Ктонибуть ПОЖАЛУЙСТА помогите!!!!!

1. $6/(2\sqrt{3}-3) - 4/(\sqrt{3}-1) -6/\sqrt{3}$ =

= $6( 2\sqrt{3}+3) /(12-9) - 4 (\sqrt{3}-1)/(3-1) -6 \sqrt{3} /3$ =

= $4 \sqrt{3} + 6 - 2 \sqrt{3} + 2 - 2 \sqrt{3}$ =

= 8

2. 1/(a-b)*(1/b^2-1/a^2)=

= 1/(a-b)*(1/b-1/a)(1/b+1/a)=

= 1/(a-b)*((a-b)/ab)((a+b)/ab)=

= (a+b)/(ab)^2

3. $1/(x(x-1) + (x/( (\sqrt{x}-1)( \sqrt{x}+1))-\sqrt{x}/( \sqrt{x}+1 ))/ (\sqrt{x^3}/ (x-1)$ =

= $1/(x(x-1) + ( (x - x + 1 )/( (\sqrt{x}-1)( \sqrt{x}+1) )/(\sqrt{x^3}/ (x-1)$ =

= $1/(x(x-1) +(x-1)/(x(x-1)) = (x-1+1)/(x(x-1))=1/(x-1)$