1 Вариант, пожалуйста

1.1) $x^2-5=x^2-(\sqrt{5})^2=(x-\sqrt{5})(x+\sqrt{5});$
$1.2)4z-7=(\sqrt{4z})^2-(\sqrt{7})^2=(\sqrt{4z}-\sqrt{7})(\sqrt{4z}+\sqrt{7});$
$1.3)5+\sqrt{5}=\sqrt{25}+\sqrt{5}=\sqrt{5}(\sqrt{5}+1);$
$1.4)\sqrt{20}-\sqrt{50}=\sqrt{10}(\sqrt{2}-\sqrt{5}).$
$2.1) \frac{y-9}{\sqrt{y}-3}= \frac{(\sqrt{y})^2-3^2}{\sqrt{y}-3}= \frac{(\sqrt{y}-3)(\sqrt{y}+3)}{\sqrt{y}-3}=\sqrt{y}+3;$
$2.2) \frac{\sqrt{3}+3}{\sqrt{6}+\sqrt{2}}= \frac{\sqrt{3}+\sqrt{9}}{\sqrt{2}(\sqrt{3}+1)}= \frac{\sqrt{3}(1+\sqrt{3})}{\sqrt{2}(1+\sqrt{3})}= \frac{\sqrt{3}}{\sqrt{2}};$