Cho lim x → 3 f ( x ) = − 2 . Tính lim x → 3 [ f ( x ) + 4 x − 1 ] .

13/38

Cho \(\mathop {\lim }\limits_{x \to 3} f\left( x \right) = - 2\). Tính \(\mathop {\lim }\limits_{x \to 3} \left[ {f\left( x \right) + 4x - 1} \right]\).

\(5\).

\(6\).

\(11\).

\(9\).

Giải thích

Đáp án đúng là: D

Ta có \(\mathop {\lim }\limits_{x \to 3} \left[ {f\left( x \right) + 4x - 1} \right]\)\( = \mathop {\lim }\limits_{x \to 3} f\left( x \right) + \mathop {\lim }\limits_{x \to 3} \left( {4x - 1} \right)\)\( = - 2 + 4 \cdot 3 - 1 = 9\).