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Câu hỏi: Cho ${{\log }_{a}}b=2, {{\log }_{a}}c=3$. Giá trị ${{\log }_{a}}\left( a{{b}^{2}}{{c}^{3}} \right)$ bằng
A. $11$.
B. $7$.
C. $14$.
D. $28$.
A. $11$.
B. $7$.
C. $14$.
D. $28$.
Ta có ${{\log }_{a}}\left( a{{b}^{2}}{{c}^{3}} \right)={{\log }_{a}}a+{{\log }_{a}}{{b}^{2}}+{{\log }_{a}}{{c}^{3}}=1+2{{\log }_{a}}b+3{{\log }_{a}}c=1+4+9=14$
Đáp án C.