a: \(=\dfrac{3}{11}+\dfrac{18}{66}=\dfrac{18}{66}+\dfrac{18}{66}=\dfrac{36}{66}=\dfrac{6}{11}\)
b: \(=\dfrac{2}{9}-\dfrac{5}{12}+\dfrac{3}{4}\)
\(=\dfrac{8}{36}-\dfrac{15}{36}+\dfrac{27}{36}=\dfrac{20}{36}=\dfrac{5}{9}\)
c: \(=\dfrac{3\cdot7-5}{35}\cdot\dfrac{-40-30}{16}\)
\(=\dfrac{16}{35}\cdot\dfrac{-70}{16}=-2\)
d: \(=\dfrac{1}{5}\cdot\dfrac{2-7}{4}-\dfrac{3}{4}\cdot\dfrac{4-11}{12}\)
\(=\dfrac{1}{5}\cdot\dfrac{-5}{4}-\dfrac{3}{4}\cdot\dfrac{-7}{12}\)
\(=\dfrac{-1}{4}+\dfrac{21}{48}=\dfrac{-12+21}{48}=\dfrac{9}{48}=\dfrac{3}{16}\)