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Câu hỏi: Cho hai số thực dương $a,b$ với $a\ne 1.$ Khẳng định nào sau đây là đúng?
A. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{5{{\log }_{a}}b+1}{3}$.
B. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{{{\log }_{a}}b+5}{3}$.
C. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{5}{3}{{\log }_{a}}b$.
D. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{1}{5}{{\log }_{a}}b$
A. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{5{{\log }_{a}}b+1}{3}$.
B. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{{{\log }_{a}}b+5}{3}$.
C. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{5}{3}{{\log }_{a}}b$.
D. ${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{1}{5}{{\log }_{a}}b$
${{\log }_{a}}\sqrt[3]{b{{a}^{5}}}=\dfrac{1}{3}{{\log }_{a}}\left( b{{a}^{5}} \right)=\dfrac{1}{3}\left( {{\log }_{a}}b+{{\log }_{a}}{{a}^{5}} \right)$ $=\dfrac{1}{3}\left( {{\log }_{a}}b+5 \right)=\dfrac{{{\log }_{a}}b+5}{3}$
Đáp án B.