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a fost răspuns

lg^2 x^2 + 3lg 1/x = 1

Răspuns :

Geoo1off
(2lg x)^2-3lgx-1=0
Notez lg x=t ,(lg x)^2=t^2, t>0
4t^2-3t-1=0
Delta=9+16=25 rad delta= 5
t1=3+5/8=1
t2=3-5/8=-1/4 t<0 deci nu respecta conditia
lg x = 1 => x=10

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