Question

Giúp mik!!

Answer 1

a) \(\dfrac{1}{2}\left(\dfrac{2}{9}+\dfrac{3}{7}-\dfrac{5}{27}\right)=\dfrac{1}{2}\left(\dfrac{42}{189}+\dfrac{81}{189}-\dfrac{35}{189}\right)=\dfrac{1}{2}.\dfrac{88}{189}=\dfrac{44}{189}\)

b) \(\dfrac{1}{3}.\dfrac{5}{7}-\dfrac{7}{27}.\dfrac{36}{14}=\dfrac{5}{21}-\dfrac{1}{3}.\dfrac{4}{2}=\dfrac{5}{21}-\dfrac{1}{3}.2=\dfrac{5}{21}-\dfrac{2}{3}=\dfrac{5}{21}-\dfrac{14}{21}=\dfrac{-9}{21}=\dfrac{-3}{7}\)

d) \(\dfrac{1}{2}+\dfrac{3}{4}-\left(\dfrac{3}{4}-\dfrac{4}{5}\right)=\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{3}{4}+\dfrac{4}{5}=\dfrac{1}{2}+\dfrac{4}{5}=\dfrac{5}{10}+\dfrac{8}{10}=\dfrac{15}{10}=\dfrac{3}{2}\)

c)\(\left(\dfrac{3}{8}+\dfrac{-3}{4}+\dfrac{7}{12}\right):\dfrac{5}{6}+\dfrac{1}{2}=\left(\dfrac{9}{24}+\dfrac{-18}{24}+\dfrac{14}{24}\right).\dfrac{6}{5}+\dfrac{1}{2}=\dfrac{5}{24}.\dfrac{6}{5}+\dfrac{1}{2}=\dfrac{1}{4}+\dfrac{1}{2}=\dfrac{1}{4}+\dfrac{2}{4}=\dfrac{3}{4}\)

Answer 2

a.=1/2 x 88/189

= 44/189

b. = 5/21-3/2

= -53/42

c. = (3/8+9/12-7/12):5/6+1/2

=13/24:5/6+1/2

= 13/20+23/20

=9/10

Câu d từ từ cái để làm