a) \(M=\dfrac{\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{3}{7}-\dfrac{3}{11}}{\dfrac{6}{4}+\dfrac{6}{5}+\dfrac{6}{7}-\dfrac{6}{11}}=\dfrac{3\left(\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{11}\right)}{6\left(\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{11}\right)}=\dfrac{3}{6}=\dfrac{1}{2}\)
b) \(M=\dfrac{8-\dfrac{8}{5}+\dfrac{8}{25}-\dfrac{8}{125}}{9-\dfrac{9}{5}+\dfrac{9}{25}-\dfrac{9}{125}}:\dfrac{161616}{151515}=\dfrac{8\left(1-\dfrac{1}{5}+\dfrac{1}{25}-\dfrac{1}{125}\right)}{9\left(1-\dfrac{1}{5}+\dfrac{1}{25}-\dfrac{1}{125}\right)}:\dfrac{16\cdot10101}{15\cdot10101}\)
\(=\dfrac{8}{9}:\dfrac{16}{15}=\dfrac{8}{9}\cdot\dfrac{15}{16}=\dfrac{5}{6}\)
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