a) \(53\times128+215\times128\)
\(=128\left(53+215\right)\)
\(=128\times268=34304\)
b) \(\dfrac{8}{25}:\dfrac{2}{11}+\dfrac{7}{15}:\dfrac{2}{11}\)
\(=\dfrac{8}{25}\times\dfrac{11}{2}+\dfrac{7}{15}\times\dfrac{11}{2}\)
\(=\dfrac{11}{2}\left(\dfrac{8}{25}+\dfrac{7}{15}\right)\)
\(=\dfrac{11}{2}\times\dfrac{59}{75}=\dfrac{263}{50}\)