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rezolvati in multimea numerelor reale ecuatia log5(x^2-4)=log5(5x-8)

Răspuns :

C.E 1.x^2-4>0 <=> x^2>4 <=> x>+-2
2.5x-8>0 <=> 5x>8 <=> x>8/5
Din 1. si 2. => x>2

x^2-4=5x-8
x^2-5x+4=0
Delta= (-5)^2-4*1*4=25-16=9
X1= (5-3)/2=2/2=1
X2=(5+3)/2=8/2=4