㏒₁/₆(12-2x)=-2 ОДЗ 12-2х>0 , x< 6
12-2x=(1/6)⁻²
12-2x=36
2x=-24
x=-12
------------------------------------------------------------------------------------
㏒₄(x²+3x)= ㏒₄(x²+3) ОДЗ х²+3х>0 ,x>0
x²+3x=x²+3
3x= 3
x=1
---------------------------------------------------------------------------
lg²x-3lgx+2=0
lgx=a
a²-3a+2=0
D=9-8=1
a₁=(3+1)/2=2 lgx=2 x₁=10²=100
a₂=(3-1)/2=1 lgx=1 x₂=10¹= 10