\[\boxed{\text{1192.}\text{\ }еуроки - ответы\ на\ пятёрку}\]
\[\textbf{а)}\ \text{M\ }( - 1;1)\ и\ \text{P\ }(4;4):\]
\[\left\{ \begin{matrix} 1 = - k + b\ \ | \cdot ( - 1) \\ 4 = 4k + b\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \Longrightarrow\]
\[\Longrightarrow \left\{ \begin{matrix} k - b = - 1 \\ 4k + b = 4\ \\ \end{matrix} \right.\ \Longrightarrow\]
\[\Longrightarrow \left\{ \begin{matrix} 5k = 3 \Longrightarrow k = \frac{3}{5} = 0,6\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ b = k + 1 \Longrightarrow b = 0,6 + 1 = 1,6 \\ \end{matrix} \right.\ \]
\[\Longrightarrow \ y = 0,6x + 1,6.\]
\[\textbf{б)}\ \text{A\ }( - 3;3)\ и\ \ \ \text{B\ }(3;\ - 3):\]
\[\left\{ \begin{matrix} 3 = - 3k + b \\ - 3 = 3k + b \\ \end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix} b = 0\ \ \ \ \ \\ 3 = - 3k \\ \end{matrix} \right.\ \Longrightarrow\]
\[\Longrightarrow \left\{ \begin{matrix} b = 0\ \ \ \\ k = - 1 \\ \end{matrix} \right.\ \Longrightarrow y = - x.\]