log₅ [(1 - 2x)/(x + 3)] = 1
ОДЗ: (1 - 2x)/(x + 3) > 0
x₁ = 1/2
x₂ ≠ - 3
x∈ = (- 3;1/2)
(1 - 2x)/(x + 3) = 5¹
(1- 2x) = 5*(x + 3)
1 - 2x = 5x + 15
7x = - 14
x = - 2