\[f(x) = - \frac{1}{3}x + 2\]
\[f(x) = 1:\]
\[1 = - \frac{1}{3}x + 2\]
\[\frac{1}{3}x = 2 - 1\]
\[\frac{1}{3}x = 1\]
\[x = 3.\]