ГДЗ по алгебре 7 класс Макарычев Задание 361

\[\boxed{\text{361\ (361).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[Линейная\ функция\ имеет\ вид:\ \ \ \ \]

\[y = kx + b.\]

\[\textbf{а)}\ (0; - 8):\]

\[- 8 = 0 \cdot k + b\]

\[b = - 8;\]

\[(2;12):\]

\[12 = 2k - 8\]

\[k = 10.\]

\[Тогда\ уравнение\ прямой:\ \ \ \]

\[y = 10x - 8.\]

\[если\ x = - 2:\]

\[y = 10 \cdot ( - 2) - 8 = - 20 - 8 =\]

\[= - 28;\]

\[если\ x = 4:\]

\[y = 10 \cdot 4 - 8 = 40 - 8 = 32;\]

\[если\ x = 6:\]

\[y = 10 \cdot 6 - 8 = 60 - 8 = 52.\]

\[\textbf{б)}\ (0;5):\]

\[0 \cdot k + b = 5\]

\[b = 5;\]

\[(10;6):\]

\[6 = 10k + 5\]

\[10k = 1\]

\[k = 1\ :10\]

\[k = 0,1.\]

\[Тогда\ уравнение\ прямой:\ \ \ \]

\[y = 0,1x + 5.\]

\[если\ x = - 10:\]

\[y = 0,1 \cdot ( - 10) + 5 = - 1 + 5 =\]

\[= 4;\]

\[если\ x = 30:\]

\[y = 0,1 \cdot 30 + 5 = 3 + 5 = 8;\]

\[если\ y = - 15:\]

\[\ - 15 = 0,1x + 5\ \ \]

\[0,1x = - 20\]

\[x = - 20\ :0,1 = - 200\ :1\]

\[x = - 200.\]

\[если\ \ y = 15:\]

\[15 = 0,1x + 5\]

\[0,1x = 10\]

\[x = 10\ :0,1 = 100\ :1\]

\[x = 100.\]