\[y = \frac{18}{x}:\]
\[значение\ аргумента,\ \]
\[при\ котором\ значение\ \]
\[функции\ равно\ 6;\ - 54;40.\]
\[y = \frac{18}{x} \Longrightarrow x = \frac{18}{y}\]
\[y = 6 \Longrightarrow x = \frac{18}{6} = 3;\]
\[y = - 54 \Longrightarrow x = \frac{18}{- 54} = - \frac{1}{3};\]
\[y = 40 \Longrightarrow x = \frac{18}{40} = \frac{9}{20} = 0,09.\]