Помогите пожалуйста срочно прошу

$1) \frac{3c-6}{c+2}-\frac{c}{(c+2)^2} : \frac{c}{c^2-4} - \frac{4c}{c+2}= \frac{3c-6}{c+2}-\frac{c}{(c+2)^2} * \frac{(c-2)(c+2)}{c} - \frac{4c}{c+2}=$ $\frac{3c-6}{c+2}-\frac{c-2}{c+2} - \frac{4c}{c+2}= \frac{3c-6-c+2-4c}{c+2}= \frac{-2c-4}{c+2}= \frac{-2(c+2)}{(c+2)}=-2;$
$2.1)(\sqrt{6}+\sqrt{3})*\sqrt{12} -2\sqrt{6}*\sqrt{3}=$
$=\sqrt{4*3}*\sqrt{6}+\sqrt{4*3}*\sqrt{3}-2\sqrt{6}*\sqrt{3}=2\sqrt{18}+2\sqrt{9}-2\sqrt{18}$ $=2*3=6;$
$2.2) \frac{a-b}{\sqrt{a}-\sqrt{b}}- \frac{a-\sqrt{ab} }{\sqrt{a}-\sqrt{b} } =\frac{\sqrt{ab}-b }{\sqrt{a}-\sqrt{b} }= \frac{(\sqrt{ab}-b)(\sqrt{a}+\sqrt{b})}{( \sqrt{a}-\sqrt{b})(\sqrt{a}+\sqrt{b}) } =$ $=\frac{a\sqrt{b}+b\sqrt{a}-b\sqrt{a}-b\sqrt{b}}{a-b}= \frac{\sqrt{b}(a-b)}{(a-b)}=\sqrt{b};$