Question

Tính :

C = ( \(\dfrac{9}{10}\) - \(\dfrac{15}{16}\) ) . ( \(\dfrac{5}{12}\) - \(\dfrac{11}{15}\) - \(\dfrac{7}{20}\) )

Answer 1

\(C=\left(\dfrac{9}{10}-\dfrac{15}{16}\right).\left(\dfrac{5}{12}-\dfrac{11}{15}-\dfrac{7}{20}\right)\)

\(C=\left(\dfrac{72}{80}-\dfrac{75}{80}\right).\left(\dfrac{25}{60}-\dfrac{44}{60}-\dfrac{21}{60}\right)\)

\(C=\left(-\dfrac{3}{80}\right).\left(-\dfrac{2}{3}\right)\)

\(C=\dfrac{1}{40}\)

Answer 2

\(C=\left(\dfrac{9}{10}-\dfrac{15}{16}\right).\left(\dfrac{5}{12}-\dfrac{11}{15}-\dfrac{7}{20}\right)\\ E=\left(\dfrac{72}{80}-\dfrac{75}{80}\right).\left(\dfrac{25}{60}-\dfrac{44}{60}-\dfrac{21}{60}\right)\\ E=-\dfrac{3}{80}.\left(-\dfrac{47}{60}\right)\\ E=\dfrac{141}{4800}\)

Vây E=...

Answer 3

C=( \(\dfrac{72}{80}-\dfrac{75}{80}\) ).(\(\dfrac{25}{60}\)\(-\)\(\dfrac{44}{60}\)\(-\)\(\dfrac{21}{60}\))

C=\(-\dfrac{3}{80}\).(\(-\dfrac{2}{3}\))

C=\(\dfrac{1}{40}\)