viktorkivkov Π(8х +6)/9 = +-arcCos(-1/2) + 2πk, k∈Z
π(8х +6)/9 = +- 2π/3 + 2πk, k∈Z
(8x + 6)/9 = +- 2/3 + 2k, k∈Z
8x + 6 = +-6 + 18k, k ∈Z
8x = -6 +-6 + 18k, k ∈Z
x = -3/4 +-3/4 + 4,5k, k∈Z
1) k = 0                         3)k = 0
x = -3/4 +3/4= 0              x = -3/4 -3/4 = -6/4 = -1,5
2) k = 1                         4) k = 1
x = -3/4 + 3/4 + 1= 1     x = -3/4 -3/4 +1 = -0,5