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Ăquation: $~\ln(x+3) + \ln(x+2) = \ln(x+11)$
- Domaine : $\mathcal{D}_e = ]-2 ; +\infty[$.
- $\ln((x+3)(x+2)) = \ln(x+11) \iff x^2 + 5x + 6 = x + 11$
- $x^2 + 4x - 5 = 0 \implies x_1 = -5 \notin \mathcal{D}_e$ et $x_2 = 1 \in \mathcal{D}_e$.
- $S = \{1\}$
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Ăquation: $~\ln(x^2 - 4x + 3) = \ln(2x - 5)$
- Domaine : $\mathcal{D}_e = ]3 ; +\infty[$.
- $x^2 - 4x + 3 = 2x - 5 \iff x^2 - 6x + 8 = 0$
- $x_1 = 2 \notin \mathcal{D}_e$ et $x_2 = 4 \in \mathcal{D}_e$.
- $S = \{4\}$
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Ăquation: $~2\ln(x) = \ln(x+4) + \ln(2)$
- Domaine : $\mathcal{D}_e = ]0 ; +\infty[$.
- $\ln(x^2) = \ln(2x + 8) \iff x^2 - 2x - 8 = 0$
- $x_1 = -2 \notin \mathcal{D}_e$ et $x_2 = 4 \in \mathcal{D}_e$.
- $S = \{4\}$