Ta có: \(D=\dfrac{\dfrac{1}{14}-\dfrac{1}{30}-\dfrac{1}{46}}{\dfrac{2}{35}-\dfrac{2}{75}-\dfrac{2}{115}}:\dfrac{\dfrac{3}{8}-\dfrac{15}{17}+\dfrac{30}{31}}{\dfrac{1}{6}-\dfrac{20}{51}+\dfrac{40}{93}}\)
\(=\dfrac{\dfrac{1}{2}\left(\dfrac{1}{7}-\dfrac{1}{15}-\dfrac{1}{23}\right)}{\dfrac{2}{5}\left(\dfrac{1}{7}-\dfrac{1}{15}-\dfrac{1}{23}\right)}:\dfrac{3\left(\dfrac{1}{8}-\dfrac{5}{17}+\dfrac{10}{31}\right)}{\dfrac{4}{3}\left(\dfrac{1}{8}-\dfrac{5}{7}+\dfrac{10}{31}\right)}\)
\(=\dfrac{\dfrac{1}{2}}{\dfrac{2}{5}}:\dfrac{3}{\dfrac{4}{3}}\)
\(=\dfrac{1}{2}\cdot\dfrac{5}{2}:\dfrac{9}{4}\)
\(=\dfrac{5}{4}\cdot\dfrac{4}{9}=\dfrac{5}{9}\)
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4
x = ?
4 B. x = 4 C. –4 D. Một kết quả khác.