Rút gọn biểu thức: \( 2\sqrt a - \sqrt {9{a^3}} + {a^2}\sqrt {\frac{{16}}{a}} + \frac{2}{{{a^2}}}\sqrt {36{a^5}} \)

* Hướng dẫn giải

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\(\begin{array}{l} 2\sqrt a - \sqrt {9{a^3}} + {a^2}\sqrt {\frac{{16}}{a}} + \frac{2}{{{a^2}}}\sqrt {36{a^5}} = 2\sqrt a - \sqrt {9{a^2}.a} + {a^2}\frac{{\sqrt {16a} }}{a} + \frac{2}{{{a^2}}}.\sqrt {36{a^4}.a} \\ = 2\sqrt a - 3a\sqrt a + 4a\sqrt a + \frac{2}{{{a^2}}}.6{a^2}\sqrt a = 2\sqrt a - 3a\sqrt a + 4a\sqrt a + 12\sqrt a \\ = 14\sqrt a + a\sqrt a \end{array}\)