\[\boxed{\text{976\ (976).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ A\ (12;\ - 4):\]
\[12a + 4 \cdot ( - 4) = 0\]
\[12a = 16\]
\[a = \frac{4}{3} = 1\frac{1}{3}\]
\[Ответ:при\ a = 1\frac{1}{3}.\]
\[2)\ B\ (0;2):\]
\[0 + 4 \cdot 2 = 0\]
\[8 \neq 0\ не\ проходит \Longrightarrow\]
\[\Longrightarrow a - не\ существует.\]
\[3)\ \text{O\ }(0;0):\]
\[0 + 0 = 0\ \]
\[0 = 0\ \]
\[при\ a - любое\ число.\]
\[\boxed{\text{976.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[f(x) = 7x - 5\]
\[1)\ f(2) = 7 \cdot 2 - 5 = 9.\]
\[2)\ f(0) = 7 \cdot 0 - 5 = - 5.\]
\[3)\ f( - 3) = 7 \cdot ( - 3) - 5 = - 26.\]
\[4)\ f(200) = 7 \cdot 200 - 5 =\]
\[= 1400 - 5 = 1395.\]