Lg(3x-1)-lg(x+5)=lg5

Question

Lg(3x-1)-lg(x+5)=lg5

Answer 1

Решение
lg[(3x - 1)/(x + 5)] = lg5
ОДЗ: (3x - 1)*(x + 5)  > 0
x₁ = 1/3 ; x₂ = - 5
ОДЗ: x ∈ (- ∞ ; - 5) (1/3; + ∞)
(3x - 1)/(x + 5) = 5, x ≠ - 5
3x -  1 =  5x + 25
- 2x = 26
x = - 13
Ответ: x = - 13