\[y = \frac{1}{3}x^{2};\ \ \ \ x \in \lbrack - 3;6\rbrack\]
\[y( - 3) = \frac{1}{3} \cdot 9 = 3;\ \]
\[y(0) = 0;\]
\[y(6) = \frac{1}{3} \cdot 36 = 12\]
\[E(y) = \lbrack 0;12\rbrack.\]