Răspuns:
Explicație pas cu pas:
Produsul notat P(x) < 0 daca cei doi factori au semne diferite
f(x) = lnx - 1, logaritmul impune x > 0
f(x) = 0, x = e = 2,7...
Pt. x in (0, e) f(x) < 0
Pt. x in (e, +inf) f(x) > 0
p(x) = x^2 +2x -3, p(x) = 0:
delta = 4 +12 = 16
x1,2 = (-2 +-4)/2
x1 = -6/2 = -3, x2 = 2/2 = 1
p(x) = (x-1)(x+3)
Pt. x in (-3, 1) p(x) < 0 si cum x > 0, x in (0, 1)
Pt. x in (-inf, -3) U (1, +inf) p(x) >0,
si cum x > 0, x in (1, +inf)
Asadar P(x) < 0 daca x in (1, e)
