\(a.\)
\(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)
\(=\left(\dfrac{12}{12}+\dfrac{8}{12}-\dfrac{3}{12}\right).\left(\dfrac{16}{20}-\dfrac{15}{20}\right)^2\)
\(=\dfrac{17}{12}.\left(\dfrac{1}{20}\right)^2\)
\(=\dfrac{17}{12}.\dfrac{1}{400}\)
\(=\dfrac{17}{4800}\)
\(b.\)
\(2:\left(\dfrac{1}{2}-\dfrac{2}{3}\right)\)
\(=2:\left(\dfrac{3}{6}-\dfrac{4}{6}\right)\)
\(=2:\left(-\dfrac{1}{6}\right)\)
\(=2.-6\)
\(=-12\)
\(a)\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right).\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2=\dfrac{17}{12}.\dfrac{1}{400}=\dfrac{17}{4800}\)
\(b)2:\left(\dfrac{1}{2}-\dfrac{2}{3}\right)^3=2:\dfrac{-1}{216}==-432\)
Chúc bạn học tốt!
