Giới hạn lim n → + ∞ 3 n − 4 n + 5 n 3 n + 4 n − 5 n bằng

Ta có \(\mathop {\lim }\limits_{n \to + \infty } \frac{{{3^n} - {4^n} + {5^n}}}{{{3^n} + {4^n} - {5^n}}} = \mathop {\lim }\limits_{n \to + \infty } \frac{{{{\left( {\frac{3}{5}} \right)}^n} - {{\left( {\frac{4}{5}} \right)}^n} + 1}}{{{{\left( {\frac{3}{5}} \right)}^n} + {{\left( {\frac{4}{5}} \right)}^n} - 1}} = - 1\). Chọn B.