Question

Найдите значение выражения

Answer 1

$(sqrt{ frac{42}{5}}- sqrt{frac{21}{10}})* sqrt{ frac{8}{105}}= sqrt{ frac{42*8}{5*105}}- sqrt{ frac{21*8}{10*105}}= sqrt{ frac{3*7*2*8}{5*7*3*5}}- sqrt{ frac{3*7*8}{2*5*7*3*5}}= \ =sqrt{ frac{16}{25}}-sqrt{ frac{4}{25}}= frac{4}{5}- frac{2}{5}= frac{2}{5}=0.4$