Реши уравнение k-2/5*k=4,5.

\[k - \frac{2}{5}k = 4,5\]

\[k\left( 1 - \frac{2}{5} \right) = 4,5\]

\[k\left( \frac{5}{5} - \frac{2}{5} \right) = 4,5\]

\[\frac{3}{5}k = 4,5\]

\[k = 4,5\ :\frac{3}{5}\]

\[k = \frac{45}{10} \cdot \frac{5}{3}\]

\[k\frac{3 \cdot 3 \cdot 5 \cdot 5}{2 \cdot 5 \cdot 3} = \frac{15}{2}\]

\[k = 7,5\]

\[Ответ:\ \ k = 7,5.\]