Дан график линейной функции y=kx+b (см. рис. 40). Определите числа k и b.

\[y = kx + b\]

\[(1;\ - 1):\]

\[- 1 = k \bullet 1 + b\]

\[b = - 1 - k.\]

\[(4;0):\]

\[0 = k \bullet 4 + b\]

\[4k = - b\]

\[4k = - ( - 1 - k)\]

\[4k = 1 + k\]

\[3k = 1\]

\[k = \frac{1}{3}.\]

\[b = - 1 - \frac{1}{3} = - 1\frac{1}{3}.\]

\[Ответ:y = \frac{1}{3}x - 1\frac{1}{3}.\]