Log1/9(7-2x)=-2.решите уравнение

Question

Log1/9(7-2x)=-2.решите уравнение

Answer 1

ОДЗ: 7-2х>0
-2x>-7
x<3,5<br>
Log1/9(7-2x)=-(log1/9(1/9)+log1/9(1/9))
Log1/9(7-2x)=-log1/9(1/81)
Log1/9(7-2x)=log1/9(81)
7-2x=81
-2x=81-7
-2x=74
х=-37