[tex]\sqrt2(\sqrt{72}+\sqrt2)\qquad\text{use\ distributive property}\\\\=(\sqrt2)(\sqrt{72})+(\sqrt2)(\sqrt2)\qquad\text{use}\ \sqrt{a\cdot b}=\sqrt{a}\cdot\sqrt{b}\\\\=\sqrt{(2)(72)}+\sqrt{(2)(2)}\\\\=\sqrt{144}+\sqrt4\\\\=12+2=14\\\\------------------------------\\\sqrt{a}=b\iff b^2=a\\\\\sqrt{144}=12\ because\ 12^2=144\\\\\sqrt4=2\ because\ 2^2=4[/tex]