[tex]\it \mathbf{1}.\ (3\sqrt3-\sqrt{27})^2+1=(3\sqrt3-\sqrt{9\cdot3})^2+1=(3\sqrt3-3\sqrt3)^2+1=\\ \\ = 0^2+1=0+1=0[/tex]
[tex]\it \mathbf{2}.\ m_a=\dfrac{a+b}{2}=\dfrac{\sqrt2+\sqrt{18}}{2}=\dfrac{\sqrt2(1+\sqrt9)}{2}=\dfrac{\sqrt2\cdot\ 4}{2}=2\sqrt2[/tex]
[tex]\it m_g=\sqrt{a\cdot b}=\sqrt{\sqrt2\cdot\sqrt18}=\sqrt{\sqrt{36}}=\sqrt6[/tex]
