Решить №3.128 (1,2,3 условия

X(2x - 3)(x - 6) = 0
или x₁ = 0              или    2x - 3 = 0                  или  x - 6 = 0
                                       2x = 3                               x₃ = 6
                                       x₂ = 1,5

9x² - 1 = 0
(3x)² - 1² = 0
(3x - 1)(3x + 1) = 0
или     3x - 1 = 0                или     3x + 1 = 0
           3x = 1                                 3x = - 1
           x₁ = 1/3                                x₂ = - 1/3

x³ - 16x = 0
x(x² - 16) = 0
x(x - 4)(x + 4) = 0
или     x₁ = 0             или    x - 4 = 0        или   x + 4 = 0
                                           x₂ = 4                      x₃ = - 4

Решение
log₂ sin(x/2) < - 1
ОДЗ: sinx/2 > 0
2πn < x/2 < π + 2πn, n ∈ Z
4πn < x < 2π + 4πn, n ∈ Z
sin(x/2) < 2⁻¹
sin(x/2) < 1/2
- π - arcsin(1/2) + 2πn < x/2 < arcsin(1/2) + 2πn, n ∈ Z
- π - π/6 + 2πn < x/2 < π/6 + 2πn, n ∈ Z
- 7π/6 + 2πn < x/2 < π/6 + 2πn, n ∈ Z
- 7π/3 + 4πn < x < π/3 + 4πn, n ∈ Z
2)  log₁/₂ cos2x > 1
ОДЗ:
cos2x > 0
- arccos0 + 2πn < 2x < arccos0 + 2πn, n ∈ Z
- π/2 + 2πn < 2x < π/2 + 2πn, n ∈ Z
- π + 4πn < x < π + 4πn, n ∈ Z
так как 0 < 1/2 < 1, то
cos2x < 1/2
arccos(1/2) + 2πn < 2x < 2π - arccos(1/2) + 2πn, n ∈ Z
π/3 + 2πn < 2x < 2π - π/3 + 2πn, n ∈ Z
π/6 + πn < x < 5π/6 + πn, n ∈ Z