\[A(15; - 7):\]
\[y = kx - 12\]
\[- 7 = 15k - 12\]
\[15k = - 7 + 12\]
\[15k = 5\]
\[k = \frac{5}{15} = \frac{1}{3}.\]
\[Ответ:k = \frac{1}{3}.\]