[tex]\bf \sqrt{5}(6-6\sqrt{15})\implies \stackrel{\textit{distributing}}{6\sqrt{5}-6\sqrt{15}\cdot \sqrt{5}}\implies 6\sqrt{5}-6\sqrt{15\cdot 5} \\\\\\ 6\sqrt{5}-\sqrt{3\cdot 5\cdot 5}\implies 6\sqrt{5}-\sqrt{3\cdot 5^2}\implies 6\sqrt{5}-5\sqrt{3}[/tex]
