Lg(x-4) + lg(x+3) = lg(5x+4)
{x-4>0⇒x>4 {x+3>0⇒x>-3 {5x+4>0⇒x>-0,8 x∈(4;∞) lg[(x-4)(x+3)]=lg(5x+4) (x-4)(x+3)=5x+4 x²+3x-4x-12-5x-4=0 x²-6x-16=0 x1+x2=6 U x1*x2=-16 x1=-2 не удов усл x2=8