[tex]\it \sqrt{243}\cdot\sqrt{147}-2\sqrt3\cdot7\sqrt3+3\sqrt8(5\sqrt{72} +6\sqrt{128})=
\\ \\
= \sqrt{81\cdot3}\cdot\sqrt{49\cdot3} -14\cdot3 +3\sqrt{8}(5\sqrt{9\cdot8} +6\sqrt{16\cdot8})=
\\ \\
= 9\sqrt{3}\cdot7\sqrt{3} -14\cdot3 +3\sqrt{8}(15\sqrt{8}+24\sqrt{8}) =
\\ \\
= 63\cdot3 -14\cdot3 +3\sqrt{8}\cdot39\sqrt{8} = 63\cdot3 -14\cdot3 +3\cdot8\cdot39 = [/tex]
[tex]\it = 3(63-14+312) = 3\cdot 361= 1083[/tex]
