вправа 1050 гдз 7 клас алгебра Мерзляк Полонський
7 клас ➠ алгебра ➠ Мерзляк Полонський
Вправа 1050
Відповідь:
\begin{equation}1)\left\{\begin{matrix}
5x+y=7,\\7x-4y=-1;
\end{matrix}\right.
\end{equation}
\begin{equation}+\left\{\begin{matrix}
20x+4y=28,\\7x-4y=-1;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
27x=27,\\y=7-5x;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=1,\\y=2;
\end{matrix}\right.
\end{equation}
\begin{equation}2)\left\{\begin{matrix}
6x-5y=23,\\2x-7y=13;
\end{matrix}\right.
\end{equation}
\begin{equation}-\left\{\begin{matrix}
6x-5y=23,\\6x-21y=39;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
16y=-16,\\2x=13+7y;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=-1,\\2x=6;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
y=-1,\\x=3;
\end{matrix}\right.
\end{equation}
\begin{equation}3)\left\{\begin{matrix}
5x-2y=16,\\8x+3y=38;
\end{matrix}\right.
\end{equation}
\begin{equation}+\left\{\begin{matrix}
15x-6y=48,\\16x+6y=76;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
31x=124,\\2y=5x-16;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=4,\\2y=4;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=4,\\y=2;
\end{matrix}\right.
\end{equation}
\begin{equation}4)\left\{\begin{matrix}
5x-4y=10,\\2x-3y=-3;
\end{matrix}\right.
\end{equation}
\begin{equation}-\left\{\begin{matrix}
10x-8y=20,\\10x-15y=-15;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
2x=3y-3,\\7y=35;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
2x=12,\\y=5;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
x=6,\\y=5;
\end{matrix}\right.
\end{equation}
\begin{equation}5)\left\{\begin{matrix}
4a+6b=9,\\3a-5b=2;
\end{matrix}\right.
\end{equation}
\begin{equation}-\left\{\begin{matrix}
12a+18b=27,\\12a-20b=8;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
38b=19,\\3a=2+5b;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
b=0,5,\\3a=4,5;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
b=0,5,\\a=1,5;
\end{matrix}\right.
\end{equation}
\begin{equation}6)\left\{\begin{matrix}
9m-13n=22,\\2m+3n=-1;
\end{matrix}\right.
\end{equation}
\begin{equation}-\left\{\begin{matrix}
18m-26n=44,\\18m+27n=-9;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
2m=-1-3n,\\53n=-53;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
2m=2,\\n=-1;
\end{matrix}\right.
\end{equation}
\begin{equation}\left\{\begin{matrix}
m=1,\\n=-1.
\end{matrix}\right.
\end{equation}