= 0,6 : 5/4 + 1/4 + 2/9 : 5/9  - 1/4

 = 3/5 . 4/5  + 2/9 . 9/5

= 12/25  + 2/5

= 22/25

EEEEEEEEEEEEEE ĐÉ

\(\sqrt{1}-\sqrt{4}+\sqrt{9}-\sqrt{16}+\sqrt{25}-\sqrt{36}+...-\sqrt{400}\)

\(=1-2+3-4+5-6+...-400\)

\(=\left(1-2\right)+\left(3-4\right)+\left(5-6\right)+...+\left(399-400\right)\)

\(=-1+\left(-1\right)+\left(-1\right)+...+\left(-1\right)\) (200 số hạng -1)

\(=\left(-1\right).200=-200\)

\(\sqrt{25=5}\)   \(\sqrt{16=4}\) \(\sqrt{165=15}\) \(\sqrt{1=1}\) \(\sqrt{0=0}\) \(\sqrt{3=1,4...}\)

\(\left(\frac{2}{5}\sqrt{16}+2\sqrt{\frac{16}{25}}\right):2\sqrt{\frac{1}{16}}=\left(\frac{2}{5}.\sqrt{4^2}+2\sqrt{\frac{4^2}{5^2}}\right):\frac{2}{\sqrt{4^2}}\)

\(=\left(\frac{2}{5}.4+2.\frac{4}{5}\right).2=\left(\frac{8}{5}+\frac{8}{5}\right).2=\frac{32}{5}\)

\(\left(\frac{2}{5}.\sqrt{16}+2\sqrt{\frac{16}{25}}\right):2\sqrt{\frac{1}{16}}\)

\(=\left(\frac{2}{5}.4+2.\frac{4}{5}\right):2.\frac{1}{4}\)

\(=\left(\frac{8}{5}+\frac{8}{5}\right):\frac{1}{2}\)

\(=\frac{16}{5}:\frac{1}{2}\)

\(=\frac{32}{5}\)

 ^...^ ^_^

\(\left(\frac{2}{5}\sqrt{16}+2\sqrt{\frac{16}{25}}\right):2\sqrt{\frac{1}{16}}\)

\(=\left(\frac{2}{5}.4+2.\frac{4}{5}\right):2.\frac{1}{4}\)

\(=\left(\frac{8}{5}+\frac{8}{5}\right):\frac{1}{2}\)

\(=\frac{16}{5}:\frac{1}{2}\)

\(=\frac{16}{5}.2\)

\(=\frac{32}{5}\)

a)\(\dfrac{3}{4}-\dfrac{5}{2}-\dfrac{3}{5}=\dfrac{15}{20}-\dfrac{50}{20}-\dfrac{12}{20}=-\dfrac{47}{20}\)

b) \(\sqrt{7^2}+\sqrt{\dfrac{25}{16}-\dfrac{3}{2}}=7+\sqrt{\dfrac{1}{16}}=7+\dfrac{1}{4}=\dfrac{29}{4}\)

c) \(\dfrac{1}{2}.\sqrt{100}-\sqrt{\dfrac{1}{16}+\left(\dfrac{1}{3}\right)^0}=\dfrac{1}{2}.10-\sqrt{\dfrac{1}{16}+1}=5-\sqrt{\dfrac{17}{16}}\)

a) = \(\frac{7}{2}\)

b) = \(\frac{643}{64}\)

c) = 0