Câu hỏi: Cho $a$ là số thực dương tùy ý, khi đó ${{\log }_{2}}\left( \dfrac{{{a}^{5}}}{2\sqrt{2}} \right)$ bằng
A. $5{{\log }_{2}}a-\dfrac{3}{2}.$
B. $5{{\log }_{2}}a+\dfrac{3}{2}.$
C. $5{{\log }_{2}}a-\dfrac{2}{3}.$
D. $\dfrac{3}{2}-5{{\log }_{2}}a.$
A. $5{{\log }_{2}}a-\dfrac{3}{2}.$
B. $5{{\log }_{2}}a+\dfrac{3}{2}.$
C. $5{{\log }_{2}}a-\dfrac{2}{3}.$
D. $\dfrac{3}{2}-5{{\log }_{2}}a.$
${{\log }_{2}}\left( \dfrac{{{a}^{5}}}{2\sqrt{2}} \right)={{\log }_{2}}{{a}^{5}}-{{\log }_{2}}\left( 2\sqrt{2} \right)=5{{\log }_{2}}a-\dfrac{3}{2}$
Đáp án A.