Вправа 1092 алгебра Бевз гдз 7 клас

№ 1092 $$
\begin{aligned}
& \text { a) }\left\{\begin{array}{c}
5 x-2=4(x+2 y)-8 \\
3(2 x-y)+6=24 y+12
\end{array}\right. \\
& \left\{\begin{array}{c}
5 x-2=4 x+8 y-8 \\
6 x-3 y+6=24 y+12
\end{array}\right. \\
& \left\{\begin{array}{c}
x=8 y-6 \\
6 x-27 y=6
\end{array}\right.
\end{aligned}
$$
$$
\begin{aligned}
& 6 \cdot(8 y-6)-27 y=6 \\
& 48 y-36-27 y=6 \\
& 21 y=42 \\
& y=42: 21 \\
& y=2 \\
& x=8 \cdot 2-6 \\
& x=10
\end{aligned}
$$ Відповідь: $(10 ; 2)$ $$
\begin{aligned}
& \text { б) }\left\{\begin{array}{c}
2 x-3=5(x-y) \\
2(3 x-1)=y-35
\end{array}\right. \\
& \left\{\begin{array}{c}
2 x-3=5 x-5 y \\
6 x-2=y-35
\end{array}\right. \\
& \left\{\begin{array}{c}
3 x-5 y=-3 \\
y=6 x+33
\end{array}\right.
\end{aligned}
$$
$$
\begin{aligned}
& 3 x-5 \cdot(6 x+33)=-3 \\
& 3 x-30 x-165=-3 \\
& -27 x=162 \\
& x=162:(-27) \\
& x=-6 \\
& y=6 \cdot(-6)+33 \\
& y=-36+33 \\
& y=-3
\end{aligned}
$$ Відповідь: (-6; -3)