а) 0,1 ⋅ (-1,5) = - (0,1 ⋅ 1,5) = -0,15
б) 4 ⋅ \(\frac{-10}{21}\) = - (\(\frac{4}{1}\) ⋅ \(\frac{10}{21}\)) = - \(\frac{4 ⋅ 10}{1 ⋅ 21}\) = -\(\frac{40}{21}\) = -1 \(\frac{19}{21}\)
в) (-10) ⋅ \(\frac{-25}{41}\) = \(\frac{10}{1}\) ⋅ \(\frac{25}{41}\) = \(\frac{10 ⋅ 25}{1 ⋅ 41}\) = \(\frac{250}{41}\) = 6 \(\frac{4}{41}\)
Ответ: а) -0,15; б) -1 \(\frac{19}{21}\); в) 6 \(\frac{4}{41}\)