А)
-2(х+5) + 1 = - 3(х +1)
-2х - 10 + 1 = -3х - 3
-2х - 9 = -3х - 3
-2х + 3х = -3 +9
х = 6
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-2(6+5) + 1 = -3(6+1)
-22 + 1 = - 3 * 7
-21 = -21
б)
0,8(9+2х) = 1 - 1 ¹/₂ *х
7,2 + 1,6х = 1 - 1,5х
1,6х + 1,5х = 1 - 7,2
3,1х = - 6,2
х = -6,2 / 3,1
х = - 2
=======================
0,8 (9+ 2 *(-2)) = 1 - 1 ¹/₂ * (-2)
0,8 * (9 - 4) = 1 - ³/₂ * (-²/₁)
0,8 * 5 = 1 + 3
4=4
в)
(х -4,5) / 2 = (-2х - 3,5) /3
3(х-4,5) = 2 *(-2х - 3,5)
3х - 13,5 = -4х - 7
3х + 4х = -7+13,5
7х= 6,5
х= 6,5/7 = 65/70 = 13/14
х=¹³/₁₄
======================
(¹³/₁₄ - 4,5) / 2 = (-2 * ¹³/₁₄ - 3,5) / 3
(¹³/₁₄ - ⁹/₂) / 2 = ( - ²⁶/₁₄ - ⁷/₂) /3
(¹³/₁₄ - ⁶³/₁₄) / 2 = ( - ²⁶/₁₄ - ⁴⁹/₁₄) /3
- ⁵⁰/₁₄ * ¹/₂ = - ⁷⁵/₁₄ * ¹/₃
- ²⁵/₁₄ = - ²⁵/₁₄
- 1 ¹¹/₁₄ = - 1 ¹¹/₁₄
г)
|x| - 15 = 9 - 5 * |x|
x≥0
x - 15 = 9 - 5x
x +5x = 9 + 15
6x = 24
x=24/6
x₁ = 4
x<0<br>-x -15 = 9 - 5 *(-x)
-x - 15 = 9 +5x
-x - 5x = 9 + 15
-6x = 24
x= 24/(-6)
x₂ = - 4