\[f(x) = \frac{1}{3}x^{2} - 2x\]
\[f( - 6) = \frac{1}{3} \cdot ( - 6)^{2} - 2 \cdot ( - 6) =\]
\[= \frac{1}{3} \cdot 36 + 12 = 12 + 12 = 24.\]
\[f(2) = \frac{1}{3} \cdot 4 - 2 \cdot 2 = \frac{4}{3} - 4 =\]
\[= 1\frac{1}{3} - 4 = - 2\frac{2}{3}.\]