Question

tính hợp lí

(9,75.21/3/7+39/4.18/4/7).15/78

Answer 1

bn ơi bn có thể viết đề rõ ràng được không

Answer 2

\(\left(9,75.21\dfrac{3}{7}+\dfrac{39}{4}.18\dfrac{4}{7}\right).\dfrac{15}{78}\)

\(=\left(\dfrac{39}{4}.\dfrac{150}{7}+\dfrac{39}{4}+\dfrac{130}{7}\right).\dfrac{15}{78}\)

\(=\dfrac{39}{4}.\left(\dfrac{150}{7}+\dfrac{130}{7}\right).\dfrac{15}{78}\)
\(=\dfrac{39}{4}.40.\dfrac{15}{78}\)

\(=390.\dfrac{15}{78}\)

\(=75\)