lg10x = 3-lg10 ( 2x + 10 )

(lg0.1+lgx)(lg10+lgx)=3
(lgx-1)(lgx+1)=3
(lgx)^2-1=3
(lgx)^2-4=0
(lgx-2)(lgx+2)=0
lgx=2 или lgx=-2
x=10^2=100 или x=10^(-2)=0.01

Ответ: 100,0.01