Câu hỏi: Cho $I=\int\limits_{0}^{2}{f\left( x \right)\text{d}x=3}$. Khi đó $J=\int\limits_{0}^{2}{\left[ 4f\left( x \right)-3 \right]\text{d}x}$ bằng
A. $2$.
B. $6$.
C. $8$.
D. $4$.
A. $2$.
B. $6$.
C. $8$.
D. $4$.
Ta có $J=\int\limits_{0}^{2}{\left[ 4f\left( x \right)-3 \right]\text{d}x}=4\int\limits_{0}^{2}{f\left( x \right)\text{d}x}-3\int\limits_{0}^{2}{\text{d}x}=4.3-\left. 3x \right|_{0}^{2}=6$.
Đáp án B.