Question

СРОЧНО РЕБЯТ ПОМОГИТЕЕЕЕЕЕ

Answer 1

1 вариант:

{ (5-x)/3 >= 3x-5

{ (5-x)/3 <= 7+x

{ 5-x >= 9x-15

{ 5-x <= 21+3x

{ 10x <= 20

{ 4x >= -16

{ x <= 2

{ x >= -4

2 вариант:

3x - 5 <= (5 - x) / 3 <= 7 + x

9x - 15 <= 5 - x <= 21 + 3x

9x - 20 <= -x <= 16 + 3x

16 + 3x <= x <= 9x - 20 (Или же -9x + 20 >= x >= -3x - 16)

{ x <= -9x + 20

{ x >= -3x - 16

{ 10x <= 20

{ 4x >= -16

Ответ: x ∈ [-4; 2]

P.S. Где "{" - часть системы уравнений.

Answer 2

Ответ:

$3x-5\leq \dfrac{5-x}{3}\leq 7+x\ \ \Big|\cdot 3\\\\\\9x-15\leq 5-x\leq 3x+21\ \ \Big|-5\\\\9x-20\leq -x\leq 3x+16\\\\-3x-16\leq x\leq 20-9x\\\\\\\left\{\begin{array}{l}x\leq 20-9x\\x\geq -3x-16\end{array}\right\ \ \left\{\begin{array}{l}10x\leq 20\\4x\geq -16\end{array}\right\ \ \left\{\begin{array}{l}x\leq 2\\x\geq -4\end{array}\right\ \ \ \ \Rightarrow \\\\\\-4\leq x\leq 2\ \ \ \Rightarrow \ \ \ \ x\in [-4\ ;2\ ]$