[tex]5 \sqrt{ 72}-2 \sqrt{ 50}-4 \sqrt{ 8 } =\\\\=5 \sqrt{ 36\cdot 2}-2 \sqrt{ 25\cdot 2}-4 \sqrt{4\cdot 2}\\\\=5 \sqrt{ 36 }\cdot\sqrt{ 2}-2 \sqrt{ 25}\cdot\sqrt{ 2}-4 \sqrt{4 }\cdot\sqrt{ 2}\\\\=5\cdot 6\sqrt{2} -2\cdot 5\sqrt{2} -4\cdot 2\sqrt{2}= \\\\= 30\sqrt{2} -10\sqrt{2} -8\sqrt{2} =12\sqrt{2} [/tex]
