Ta có
\(\left(\dfrac{1}{2}.\sqrt{\dfrac{1}{2}}-\dfrac{3}{2}\sqrt{4,5}+\dfrac{2}{5}\sqrt{50}\right)\)\(:\dfrac{4}{15}\sqrt{\dfrac{1}{8}}\)
\(= \left( {\dfrac{1}{2}.\dfrac{{\sqrt 2 }}{2} - \dfrac{3}{2}.\sqrt {\dfrac{9}{2}} + \dfrac{2}{5}.\sqrt {25.2} } \right)\)\(:\dfrac{4}{{15}}\sqrt {\dfrac{1}{8}} \)
\(= \left( {\dfrac{{\sqrt 2 }}{4} - \dfrac{3}{2}.\dfrac{{3\sqrt 2 }}{2} + \dfrac{2}{5}.5\sqrt 2 } \right)\)\(:\left( {\dfrac{4}{{15}}.\dfrac{{\sqrt 2 }}{4}} \right)\)
\(= \left( {\dfrac{{\sqrt 2 - 9\sqrt 2 + 8\sqrt 2 }}{4}} \right):\dfrac{{\sqrt 2 }}{{15}}\)
\(= 0:\dfrac{{\sqrt 2 }}{{15}} = 0\)
