Zjednodušte:

1. $\displaystyle \frac{\sqrt{27}}{\sqrt{3}-\sqrt{12}}=$	2. $\displaystyle \frac{\sqrt{18}-\sqrt{8}}{\sqrt{18}+\sqrt{8}}=$
3. $\displaystyle \left(\frac{\sqrt{12}-\sqrt{6}}{\sqrt{12}+\sqrt{6}}\right)^2=$	4. $\displaystyle \frac{1-\sqrt{2}-\sqrt{3}}{1+\sqrt{2}+\sqrt{3}}=$
4. $\displaystyle \frac{x^4-1}{x-1}=$	6. $\displaystyle \frac{(x-1)[(x+1)^2-x]}{x^3-1}=$

7. $(x+y+1)(x-y-1)-(x-y)(x+y)=$

8. $\displaystyle \frac{ax+3a+x^2+3x}{2x(x+a)+6x+6a} =$

9. $\displaystyle \frac{\left(\frac{x}{y}+\frac{y}{x}-1\right)\left(\frac{x}{y}+\frac{y}{x}+1\right)(x^2-y^2)}{\frac{x^4}{y^2}-\frac{y^4}{x^2}}=$

10. $\displaystyle 6a+\left(\frac{a}{a-2}-\frac{a}{a+2}\right):\frac{4a}{a^4-2a^3+8a-16}=$