вправа 1037 гдз 7 клас алгебра Мерзляк Полонський
7 клас ➠ алгебра ➠ Мерзляк Полонський
Вправа 1037
Відповідь:
\begin{equation}1)\left\{\begin{matrix}
5x+2y=15,\\ 8x+3y=20;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=\frac{15-5x}{2},\\\frac{16x}{2}+\frac{3\left ( 15-5x \right )}{2} =\frac{40}{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=\frac{15-5x}{2},\\ 16x+45-15x=40;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=20,\\ x=-5;
\end{matrix}\right.
\end{equation}
\begin{equation}2)\left\{\begin{matrix}
7x+4y=5,\\ 3x+2y=3;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
7x+2\left ( 3-3x \right )=5,\\y=\frac{3-3x}{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
7x+6-6x=5,\\ y=\frac{3-3x}{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=-1,\\ y=3;
\end{matrix}\right.
\end{equation}
\begin{equation}3)\left\{\begin{matrix}
8p-5q=-11,\\ 5p-4q=-6;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
\frac{8\left ( 4q-6 \right )}{5}-\frac{25q}{5}=-\frac{55}{5},\\p=\frac{4q-6}{5};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
32q-48-25q=-55,\\ p=\frac{4q-6}{5};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
7q=-7,\\ p=\frac{4q-6}{5};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
q=-1,\\ p=-2;
\end{matrix}\right.
\end{equation}
\begin{equation}4)\left\{\begin{matrix}
6u-5\upsilon =-38,\\ 2u+7\upsilon =22;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
3\left ( 22-7\upsilon \right )-5\upsilon =-38,\\ u=\frac{22-7\upsilon }{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
66-21\upsilon -5\upsilon =-38,\\ u=\frac{22-7\upsilon }{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
-26\upsilon =-104,\\ u=\frac{22-7\upsilon }{2};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
\upsilon =4,\\ u=-3.
\end{matrix}\right.
\end{equation}