13: \(=10\cdot6\sqrt{2}-\dfrac{5}{3}\cdot9\sqrt{2}+8\sqrt{2}-2\cdot5\sqrt{2}+7\sqrt{2}\)
\(=60\sqrt{2}-15\sqrt{2}+15\sqrt{2}-10\sqrt{2}=50\sqrt{2}\)
14: \(=15\sqrt{2}-14\sqrt{2}-13\sqrt{2}+11\sqrt{2}-12\sqrt{2}\)
\(=-\sqrt{2}-12\sqrt{2}=-13\sqrt{2}\)
15: \(=\dfrac{1}{9}\cdot9\sqrt{2}-\dfrac{3}{4}\cdot8\sqrt{2}+\dfrac{11}{13}\cdot13\sqrt{2}-\dfrac{7}{24}\cdot12\sqrt{2}\)
\(=\sqrt{2}-6\sqrt{2}+11\sqrt{2}-\dfrac{7}{2}\sqrt{2}\)
\(=\dfrac{5}{2}\sqrt{2}\)
16: \(=5\cdot2\sqrt{3}-2\cdot4\sqrt{3}+6\cdot5\sqrt{3}-6\sqrt{3}\)
=10căn 3-8căn 3+30căn 3-6căn 3
=26căn 3
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