|13 - 2x | ≥ |4x - 9|
(13 - 2x - (4x - 9))(13 - 2x + (4x - 9)) ≥ 0
(13 - 2x - 4x + 9)(13 - 2x + 4x - 9) ≥ 0
(22 - 6x)(2x + 4) ≥ 0
- 6(x - 22/6)* 2(x + 2) ≥ 0
(x - 11/3)(x + 2) ≤ 0
+ - +
_________[-2]________[3 2/3]____________
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Ответ : x ∈ [ - 2 ; 3 2/3]
Ответ: 6,5; <span>√41; </span><span>2<span>√10</span></span>
-х+у = 1
х+2у = 3
___________________
у = х+1
х+2(х+1) = 3
___________________
х+2(х+1) = 3
х+2х+2 = 3
3х = 3-2
3х = 1
х = 1/3
у = х+1
у = 1 (целая) и 1/3
Ответ: х = 1/3; y = 1 целая 1/3.
5(х+1)-13>=7х+20
5х+5-13>=7х+20
5х-8>=7х+20
5х-7х>=20+8
-2x>=28
X>=-14
(-14;+бесконечность)
Сделаем замену: пусть (x-3)² = t, тогда:
t² -5t - 14 = 0
D = 25 + 56 = 81 = 9²
t₁ =
t₂ =
1) (x - 3)² = 7
x² - 6x + 9 - 7 = 0
x² - 6x + 2 = 0
D = 36 - 8 = 28 = 2√7
x₁ = 3 + √7
x₂ = 3 - √7
2) (x - 3)² = -2
x² - 6x + 9 + 2 = 0
x² - 6x + 11 = 0
D = 36 - 44 = ∅