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Câu hỏi: Nếu $\int\limits_{-1}^{1}{f\left( x \right)\text{d}x=2}$ và $\int\limits_{-1}^{1}{g\left( x \right)\text{d}x=-7}$ thì $\int\limits_{-1}^{1}{\left[ f\left( x \right)-\dfrac{1}{7}g\left( x \right) \right]\text{d}x}$ bằng
A. $1$.
B. $-3$.
C. $-1$.
D. $3$.
A. $1$.
B. $-3$.
C. $-1$.
D. $3$.
Ta có $\int\limits_{-1}^{1}{\left[ f\left( x \right)-\dfrac{1}{7}g\left( x \right) \right]\text{d}x}=\int\limits_{-1}^{1}{f\left( x \right)\text{d}x}-\dfrac{1}{7}\int\limits_{-1}^{1}{g\left( x \right)\text{d}x}=3$.
Đáp án D.