Đáp án:
\(\begin{array}{l}
1)7\sqrt 3 \\
2)4\sqrt 3 \\
3)13\sqrt 3 \\
4) - 8\sqrt 3 \\
5)6\sqrt 2 \\
6)\dfrac{{23}}{{5\sqrt 3 }}\\
7)2\sqrt 2
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
1)2.5\sqrt 3 - 3.2\sqrt 3 + 3\sqrt 3 \\
= \left( {10 - 6 + 3} \right)\sqrt 3 = 7\sqrt 3 \\
2)2\sqrt 3 + 5\sqrt 3 - 3\sqrt 3 \\
= \left( {2 + 5 - 3} \right)\sqrt 3 = 4\sqrt 3 \\
3)3\sqrt 3 - 2\sqrt 3 + 5\sqrt 3 + 7\sqrt 3 \\
= \left( {3 - 2 + 5 + 7} \right)\sqrt 3 = 13\sqrt 3 \\
4)2\sqrt 3 + 4\sqrt 3 - 5\sqrt 3 - 9\sqrt 3 \\
= \left( {2 + 4 - 5 - 9} \right)\sqrt 3 = - 8\sqrt 3 \\
5)6.\dfrac{{2\sqrt 2 }}{3} - 5.\dfrac{{4\sqrt 2 }}{5} + 14.\dfrac{{3\sqrt 2 }}{7}\\
= 4\sqrt 2 - 4\sqrt 2 + 6\sqrt 2 = 6\sqrt 2 \\
6)2.\dfrac{4}{{\sqrt 3 }} - 3.\dfrac{1}{{3\sqrt 3 }} - 6.\dfrac{2}{{5\sqrt 3 }}\\
= \left( {8 - 1 - \dfrac{{12}}{5}} \right).\dfrac{1}{{\sqrt 3 }}\\
= \dfrac{{23}}{{5\sqrt 3 }}\\
7)3\sqrt 2 + 2\sqrt 2 + \dfrac{1}{5}.5\sqrt 2 - 4\sqrt 2 \\
= \left( {3 + 2 + 1 - 4} \right)\sqrt 2 = 2\sqrt 2
\end{array}\)
