Ответ:
\[y = kx + b\]
\[k = - 4;\ \ A\ (2;\ 7):\]
\[x = 2;\ \ \ \ y = 7.\]
\[7 = - 4 \cdot 2 + b\]
\[7 = - 8 + b\]
\[b = 7 + 8\]
\[b = 15.\]
\[Линейная\ функция:\]
\[y = - 4x + 15.\]
\[y = kx + b\]
\[k = - 4;\ \ A\ (2;\ 7):\]
\[x = 2;\ \ \ \ y = 7.\]
\[7 = - 4 \cdot 2 + b\]
\[7 = - 8 + b\]
\[b = 7 + 8\]
\[b = 15.\]
\[Линейная\ функция:\]
\[y = - 4x + 15.\]