a)\(\left(\dfrac{5}{6}+\dfrac{3}{8}\right)\times\dfrac{2}{7}\)
\(=\dfrac{29}{24}\times\dfrac{2}{7}\)
\(=\) \(\dfrac{29}{84}\)
b) \(\dfrac{6}{7}\times\dfrac{2}{3}\div\dfrac{5}{7}\)
= \(\dfrac{4}{7}\div\) \(\dfrac{5}{7}\)
= \(\dfrac{4}{5}\)
c) \(\dfrac{8}{9}+\dfrac{3}{4}\times\dfrac{4}{9}\)
= \(\dfrac{8}{9}+\dfrac{1}{3}\)
= \(\dfrac{5}{9}\)
Cô tích xanh cho lisa blackpink vì câu a, b đúng. Còn câu c thì em làm như sau:
c, \(\dfrac{8}{9}\) + \(\dfrac{3}{4}\) \(\times\) \(\dfrac{4}{9}\)
= \(\dfrac{8}{9}\) + \(\dfrac{1}{3}\)
= \(\dfrac{8}{9}\) + \(\dfrac{3}{9}\)
= \(\dfrac{11}{9}\)