\[Параллелен\ y = - \frac{1}{3}x + 5;\]
\[проходит\ через\ A(6; - 3);\]
\[y = ax + b;\ \ a = - \frac{1}{3}:\]
\[- 3 = - \frac{1}{3} \cdot 6 + b\]
\[- 3 = - 2 + b\]
\[b = - 1.\]
\[Формула\ функции:\]
\[y = - \frac{1}{3}x - 1.\]