284. Решите уравнение: a) -0,4y (-0,8) = −0,96; 6)3(-2,1x) = 20,16.

Ответ: a) y = -3; б) x = -16

Решение:

а) \[-0.4y \cdot (-0.8) = -0.96\]

\[0.32y = -0.96\]

\[y = \frac{-0.96}{0.32}\]

\[y = -3\]

б) \[\frac{8}{9} \cdot 3\frac{3}{5} \cdot (-2.1x) = 20.16\]

\[\frac{8}{9} \cdot \frac{18}{5} \cdot (-2.1x) = 20.16\]

\[\frac{8 \cdot 18 \cdot (-2.1x)}{9 \cdot 5} = 20.16\]

\[\frac{144 \cdot (-2.1x)}{45} = 20.16\]

\[-302.4x = 20.16 \cdot 45\]

\[-302.4x = 907.2\]

\[x = \frac{907.2}{-302.4}\]

\[x = -3\]

Ответ: a) y = -3; б) x = -16