Question

Va rog sa ma ajutati!!!❤❤❤​

Answer 1

 

$\displaystyle\bf\\Ex.~2)\\a=3\sqrt{20}-\sqrt{48}\\a=3\sqrt{4\times5}-\sqrt{16\times3}\\a=3\times2\sqrt{5}-4\sqrt{3}\\\boxed{\bf~a=6\sqrt{5}-4\sqrt{3}}\\\\\\b=\sqrt{108}-3\sqrt{8}\\b=\sqrt{36\times3}-3\sqrt{4\times2}\\b=6\sqrt{3}-3\times2\sqrt{2}\\\boxed{\bf~b=6\sqrt{3}-6\sqrt{2}}\\\\\\c=\sqrt{72}-\sqrt{12}\\c=\sqrt{36\times2}-\sqrt{4\times3}\\\boxed{\bf~c=6\sqrt{2}-2\sqrt{3}}$

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$\displaystyle\bf\\m_a=\frac{a+b+c}{3}\\\\\\m_a=\frac{6\sqrt{5}-\underline{4\sqrt{3}}+\underline{6\sqrt{3}}-\underbrace{6\sqrt{2}}+\underbrace{6\sqrt{2}}-\underline{2\sqrt{3}}}{3}\\\\Facem~reducerile.\\\\m_a=\frac{6\sqrt{5}}{3}\\\\\boxed{\boxed{\bf~m_a=2\sqrt{5}}}$