Вправа 867 алгебра Бевз гдз 7 клас

№ 867

a) 3(x + 4) + 6(11 – x) = 9
3x + 12 + 66 – 6x = 9
–3x = 9 – 78
x = –69 : (–3)
x = 23;
$$
\begin{aligned}
& \text { 6) } 8(1-x)+5(x-2)=2 \\
& 8-8 x+5 x-10=2 \\
& -3 x=2+2 \\
& x=4:(-3) \\
& x=-1 \frac{1}{3}
\end{aligned}
$$

в) 7(x – 5) – 3(2х – 6) = 10
7x – 35 – 6x + 18 = 10
x = 10 + 17
x = 27;

г) 18 + 3(x – 5) + 8x = 2(5 + 2x)
18 + 3x – 15 + 8x = 10 + 4x
11x – 4x = 10 – 3
7x = 7
x = 1.

вправи поруч

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