a) 1/5 : 1/10 -1/3 x (6/5 - 9/4) b) -7/50 x 3/16 x -50/21 x 4/7 c) 1/7 : 5/14 - 3/2 x (1/6 - 7/12) d) 3/5 x 2/27 - 3/5 x 29/27 giup em vs a

Đáp án + Giải thích các bước giải:

 a) $\dfrac{1}{5}$ : $\dfrac{1}{10}$ - $\dfrac{1}{3}$ . ( $\dfrac{6}{5}$ - $\dfrac{9}{4}$)

= $\dfrac{1}{5}$ : $\dfrac{1}{10}$ - $\dfrac{1}{3}$ . ( - $\dfrac{21}{20}$)

= 2 - ( - $\dfrac{7}{20}$)

= $\dfrac{47}{20}$

b) $\dfrac{- 7}{50}$ .  $\dfrac{3}{16}$ . $\dfrac{- 50}{21}$ . $\dfrac{4}{7}$

= - $\dfrac{21}{800}$ . $\dfrac{- 50}{21}$ . $\dfrac{4}{7}$

= $\dfrac{1}{16}$ . $\dfrac{4}{7}$

= $\dfrac{1}{28}$

c) $\dfrac{1}{7}$ : $\dfrac{5}{14}$ - $\dfrac{3}{2}$ . ( $\dfrac{1}{6}$ - $\dfrac{7}{12}$)

= $\dfrac{1}{7}$ : $\dfrac{5}{14}$ - $\dfrac{3}{2}$ . ( - $\dfrac{5}{12}$)

= $\dfrac{2}{5}$ - ( - $\dfrac{5}{8}$)

= $\dfrac{41}{40}$

d) $\dfrac{3}{5}$ . $\dfrac{2}{27}$ - $\dfrac{3}{5}$ . $\dfrac{29}{27}$

= $\dfrac{2}{45}$ - $\dfrac{29}{45}$

= ( - $\dfrac{3}{5}$)