Log25(5+x)= log5(2x)

log25 (5+x) = log5 (2x)
ОДЗ:
5+x>0 и 2x>0 или
x>-5 и x>0
x>0
log(5^2) (5+x) = log5 (2x)
1\2 * log5 (5+x) = log5 (2x)
log5 (5+x)^(1\2) = log5 (2x)
(5+x)^(1\2) = 2x
5+x = 4x^2
4x^2 - x - 5 = 0
Дальше легко