Question

Помогите розвязать срочно!

Answer 1

╰⁠(⁠⸝⁠⸝⁠⸝⁠´⁠꒳⁠`⁠⸝⁠⸝⁠⸝⁠)⁠╯вибач якщо буде погана оцінка

Answer 2

1. Б

x - 5 ≥ 0

x ≥ 5 =>   x ∈ [5; +∞)

2. А

-3x < - 18 | : (-3)

x > 6,   x ∈ (6; +∞)

3. В

2x > 3x + 11

2x - 3x > 11

-x > 11 | *(-1)

x < -11,   x ∈ (-∞; -11)

4. A

$7x$ ≥ $x^{2}$

$7x - x^{2}$  ≥ 0

1) $f(x) = 7x - x^{2}$

2) $f(x) = 0$

$7x - x^{2} = 0\\x(7-x) = 0$

$x_1 = 0$  або $x_2 = 7$

3) -------[0]-------[7]------>x

$f(-1) = 7 * (-1) - (-1)^{2} = -7 - 1 = -8 < 0$  - не подходит

$f(6) = 7 * 6 - 6^2 = 42 - 36 = 6 > 0$ - подходит

$f(9) = 7 * 9 - 9^2 = 63 - 81 = -18 < 0$ - не подходит

5. A

|x| - 8 ≤ 0

x - 8 ≤ 0, x ≥ 0

-x - 8 ≤ 0, x < 0

x ∈ [0;8]

x ∈ [-8;0)

значит, x ∈ [-8;8]

6. Г

$\left \{ {{-x > -19|*(-1)} \atop {x < -20}} \right. \\\left \{ {{x < 19} \atop {x < -20}} \right.$

значит, x ∈ (-∞; -20)

7.

$-12 < 2 - \frac{7}{8}x < 9 | -2$

$-14 < -\frac{7}{8}x < 7 |* (-\frac{8}{7} )$

$16 > x > -8\\-8 < x < 16$

ответ: x ∈ (-8;16)

8.

$\left \{ {{4(x-2)+5 < 8x+17(1)} \atop {\frac{7x-2}{6}-5 < \frac{4x-1}{5} (2)}} \right.$

(1) 4(x-2) + 5 < 8x + 17

4x - 8 + 5 - 8x - 17 < 0

-4x - 20 < 0 \ :(-4)

x + 5 > 0

x > - 5,   x ∈ (-5; +∞)

(2) $\frac{7x-2}{6} -5 < \frac{4x-1}{5} | * 30$

$5(7x-2) - 150 < 6(4x-1)$

35x - 10 - 150 - 24x + 6 < 0

11x - 154 < 0

11x < 154 | : 11

x < 14, x ∈ (-∞; 14)

получили, $\left \{ {x > -5} \atop {x < 14}} \right.$

-------(-5)---------(14)---------->x

ответ: х ∈ (-5; 14)