\(b,\left(\dfrac{3}{4}-\dfrac{5}{6}\right)^2=\left(\dfrac{9}{12}-\dfrac{10}{12}\right)^2=\left(\dfrac{-1}{12}\right)^2=\dfrac{1}{144}\)
\(c,2:\left(\dfrac{1}{2}-\dfrac{2}{3}\right)^3=2:\left(\dfrac{3}{6}-\dfrac{4}{6}\right)^3=2:\left(\dfrac{-1}{6}\right)^3=2:\dfrac{-1}{216}=2.\left(-216\right)=-432\)
\(f,\left(\dfrac{1}{2}-\dfrac{2}{3}+\dfrac{5}{6}\right).\left(\dfrac{-3}{2}\right)^2=\left(\dfrac{3}{6}-\dfrac{4}{6}+\dfrac{5}{6}\right).\dfrac{9}{4}=\dfrac{2}{4}.\dfrac{9}{4}=\dfrac{9}{8}\)
\(e,\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2=\left(\dfrac{12}{12}+\dfrac{8}{12}-\dfrac{3}{12}\right).\left(\dfrac{16}{20}-\dfrac{15}{20}\right)^2=\dfrac{17}{12}.\left(\dfrac{1}{20}\right)^2=\dfrac{17}{12}.\dfrac{1}{400}=\dfrac{17}{4800}\)
b; \(=\left(\dfrac{9}{12}-\dfrac{10}{12}\right)^2=\dfrac{1}{144}\)
c: \(=2:\left(\dfrac{3}{6}-\dfrac{4}{6}\right)^3=2:\left(-\dfrac{1}{6}\right)^3=2\cdot\left(-216\right)=-432\)
d: \(=-\dfrac{2}{5}:\dfrac{4}{3}-\dfrac{1}{4}=-\dfrac{3}{5}-\dfrac{1}{4}=\dfrac{-17}{20}\)