log3(5x+1)log3x=4log3(5x+1)
одз 5x + 1 > 0 x > -1/5
x > 0
x ∈ (0, +∞)
log3(5x+1)log3x - 4log3(5x+1) = 0
log3(5x+1)(log3x - 4) = 0
log3(5x+1) = 0
5x + 1 = 1
x = 0 нет по одз
log3x - 4 = 0
x = 3^4 = 81
ответ 81
