Lời giải:
a.
$\sqrt{20}-\sqrt{45}+3\sqrt{18}+\sqrt{72}$
$=\sqrt{2^2.5}-\sqrt{3^2.5}+3\sqrt{3^2.2}+\sqrt{6^2.2}$
$=2\sqrt{5}-3\sqrt{5}+9\sqrt{2}+6\sqrt{2}$
$=-\sqrt{5}+15\sqrt{2}$
b.
\(0,1\sqrt{200}+2\sqrt{0,08}+0,4\sqrt{50}\)
\(=0,1.\sqrt{10^2.2}+2\sqrt{2.0,2^2}+0,4\sqrt{5^2.2}\)
$=0,1.10\sqrt{2}+2.0,2\sqrt{2}+0,4.5\sqrt{2}$
$=\sqrt{2}+0,4\sqrt{2}+2\sqrt{2}=3,4\sqrt{2}$
c.
\(\frac{3}{2}\sqrt{6}+2\sqrt{\frac{2}{3}}+4\sqrt{\frac{3}{2}}=\frac{3}{2}\sqrt{6}+2\sqrt{\frac{6}{3^2}}+4\sqrt{\frac{6}{2^2}}\)
\(=\frac{3}{2}\sqrt{6}+\frac{2}{3}\sqrt{6}+\frac{4}{2}\sqrt{6}=\frac{25}{6}\sqrt{6}\)
Đúng 1
Bình luận (0)
