Question

Log3(x+2)+log3(x-6)=2

Answer 1

ОДЗ
x > 6

log 3 (x + 2)(x - 6) = log 3 (9)
(x + 2)(x - 6) = 9
x^2 - 6x + 2x - 12 - 9 = 0 
x^2 - 4x - 21 = 0
D = 16 + 4*21 = 100
x1 = (4 + 10)/2 = 14/2 = 7
x2 = (4 - 10)/2 = - 6/2 = - 3  (не удовлетворяет ОДЗ)

ОТВЕТ
7