EG
Ekaterina Gridneva
Ответ
1 + log2 (x+1) = log2 (7x+2) - log2 (x-1)
ОДЗ:
x+1>0 => x> -1
7x+2>0 => x> -2/7
x-1>0 => x>1
=> x>1
log2 2 + log2 (x+1) = log2 (7x+2) - log2 (x-1)
log2 2*(x+1) = log2 (7x+2)/(x-1)
2(x+1) = (7x+2)/(x-1)
2(x+1)(x-1) = 7x+2
2x^2 - 2 = 7x+2
2x^2 - 7x - 4 = 0
x1 = 4
x2 = -1/2 - по ОДЗ не подходит =>
Ответ: x=4