вправа 1038 гдз 7 клас алгебра Мерзляк Полонський
7 клас ➠ алгебра ➠ Мерзляк Полонський
Вправа 1038
Відповідь:
\begin{equation}1)\left\{\begin{matrix}
6-5\left ( x-y \right )=7x+4y,\\ 3\left ( x+1 \right )-\left ( 6x+8y \right )=69+3y;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
-12x+y=-6,\\ -3x-11y=66;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=12x-6,\\ -3x-11\left ( 12x-6 \right )=66;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=12x-6,\\ -3x-132x+66=66;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=-6,\\ x=0;
\end{matrix}\right.
\end{equation}
\begin{equation}2)\left\{\begin{matrix}
\frac{x}{2}-\frac{y}{3}=2,\\5x-y=34;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
3x-2y=12,\\ 5x-y=34;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
3x-2\left ( 5x-34 \right )=12,\\ y=5x-34;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
3x-10x+68=12,\\ y=5x-34;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
-7x=-56,\\ y=5x-34;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=8,\\ y=6;
\end{matrix}\right.
\end{equation}
\begin{equation}3)\left\{\begin{matrix}
6y-5x=1,\\ \frac{x-1}{2}+\frac{3y-x}{4}=-4\frac{3}{4};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
6x-5y=1,\\\frac{2\left ( x-1 \right )}{4}+\frac{3y-x}{4}=-\frac{19}{4};
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
6y-5x=1,\\ x+3y=-17;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
6y+5\left ( 17+3y \right )=1,\\x=-17-3y;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
6y+85+15y=1,\\ x=-17-3y;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
21y=-84,\\ x=-17-3y;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=-4,\\ x=-5;
\end{matrix}\right.
\end{equation}
\begin{equation}4)\left\{\begin{matrix}
\frac{1,5x-3}{3}+\frac{7-3y}{8}=3,\\ \frac{2,5x-2}{3}-\frac{2y+1}{6}=x-0,5;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
8\left ( 1,5x-3 \right )+3\left ( 7-3y \right )=72,\\ 2\left ( 2,5x-2 \right )-\left ( 2y+1 \right )=6x-3;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
12x-24+21-9y=72,\\5x-4-2y-1=6x-3;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
12x-9y=75,\\-x-2y=2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
4x-3y=25,\\x=-2y-2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
4\left ( -2y-2 \right )-3y=25,\\ x=-2y-2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
-11y=33,\\ x=-2y-2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=-3,\\ x=4.
\end{matrix}\right.
\end{equation}