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lg(x la puterea2-4x+2)=lg(x-2)



Răspuns :

lg(x²-4x+2)=lg(x-2) ⇒x²-4x+2=x-2
x²-4x+2-x+2=0
x²-5x+4=0
Δ=b²-4ac ⇒Δ=5²-4·1·3=25-16=9=3²
x₁=(5+3)/2=4
x₂=(5-3)/2=1