\[\boxed{\mathbf{121}\mathbf{.}}\]
\[1)\ y = x^{4}\]
\[на\ отрезке\ x \in \lbrack - 1;\ 2\rbrack:\]
\[y_{\min} = y(0) = 0;\]
\[y_{\max} = y(2) = 2^{4} = 16.\]
\[2)\ y = x^{7}\ \]
\[на\ отрезке\ x \in \lbrack - 2;\ 3\rbrack:\]
\[y_{\min} = y( - 2) = ( - 2)^{7} = - 128;\]
\[y_{\max} = y(3) = 3^{7} = 2187.\]
\[3)\ y = x^{- 1}\]
\[на\ отрезке\ x \in \lbrack - 3;\ - 1\rbrack:\]
\[y_{\min} = y( - 1) = ( - 1)^{- 1} =\]
\[= - \frac{1}{1} = - 1;\]
\[y_{\max} = y( - 3) = ( - 3)^{- 1} = - \frac{1}{3}.\]
\[4)\ y = x^{- 2}\]
\[на\ отрезке\ x \in \lbrack 1;\ 4\rbrack:\]
\[y_{\min} = y(4) = 4^{- 2} = \frac{1}{4^{2}} = \frac{1}{16};\]
\[y_{\max} = y(1) = 1^{- 2} = 1.\]