Question

Решите неравенство: lg x+lg (x-3)<1

Answer 1

ОДЗ x>0 U x-3>0⇒x>3
x∈(3;∞)
lg(x(x-3))<1
x(x-3)<10
x²-3x-10<0
x1+x2=3 U x1*x2=-10⇒x1=-2 U x2=5
-2<x<5 U x>3
x∈(3;5)