вправа 1034 гдз 7 клас алгебра Мерзляк Полонський
7 клас ➠ алгебра ➠ Мерзляк Полонський
Вправа 1034
Відповідь:
\begin{equation}1)\left\{\begin{matrix}
y=3x-1,\\ 2x+y=9;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=3x-1,\\ 2x+3x-1=9;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=3x-1,\\ 5x=10;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=5,\\ x=2;
\end{matrix}\right.
\end{equation}
\begin{equation}2)\left\{\begin{matrix}
x=2y-8,\\ x-4y=4;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=2y-8,\\ 2y-8-4y=4;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=2y-8,\\ -2y=12;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=-20,\\ y=-6;
\end{matrix}\right.
\end{equation}
\begin{equation}3)\left\{\begin{matrix}
x=6y,\\ x+5y=88;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=6y,\\ 6y+5y=88;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=6y,\\ 11y=88;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=48,\\ y=8;
\end{matrix}\right.
\end{equation}
\begin{equation}4)\left\{\begin{matrix}
2x+y=10,\\ 4x-7y=2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=10-2x,\\ 4x-7(10-2x)=2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=10-2x,\\ 4x-70+14x=2;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=10-2x,\\ 18x=72;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=2,\\ x=4;
\end{matrix}\right.
\end{equation}
\begin{equation}5)\left\{\begin{matrix}
5y-x=8,\\ 5x-4y=23;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=5y-8,\\ 5(5y-8)-4y=23;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=5y-8,\\ 25y-40-4y=23;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=5y-8,\\ 21y=63;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=7,\\ y=3;
\end{matrix}\right.
\end{equation}
\begin{equation}6)\left\{\begin{matrix}
3x+4y=0,\\ 2x-5y=46;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=-\frac{4}{3}y,\\ 2\cdot \left ( -\frac{4}{3}y \right )-5y=46;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=-\frac{4}{3}y,\\ -\frac{8}{3}y-5y=46;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=-\frac{4}{3}y,\\ -\frac{23}{3}y=46;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=8,\\ y=-6;
\end{matrix}\right.
\end{equation}
\begin{equation}7)\left\{\begin{matrix}
15-x=2y,\\ 4x-3y=27;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=15-2y,\\ 4\left ( 15-2y \right )-3y=27;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=15-2y,\\ 60-8y-3y=27;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=15-2y,\\ -11y=-33;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=9,\\ y=3;
\end{matrix}\right.
\end{equation}
\begin{equation}8)\left\{\begin{matrix}
5x-y=6,2,\\ 0,8x+3y=13;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=5x-6,2;\\0,8x+3\left ( 5x-6,2 \right )=13;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=5x-6,2,\\ 0,8x+15x-18,6=13;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=5x-6,2,\\ 15,8x=31,6;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=3,8,\\ x=2.
\end{matrix}\right.
\end{equation}