A)

\(\frac{7}{12}+\frac{3}{4}\times\frac{2}{4}\)

\(=\frac{7}{12}\times\left(\frac{3}{4}+\frac{2}{4}\right)\)

\(=\frac{35}{48}\)

B)

\(\frac{8}{9}-\frac{4}{15}:\frac{2}{5}\)

\(=\frac{8}{9}-\frac{2}{3}\)

\(=\frac{6}{27}\)

v

???

\(a,\dfrac{7}{12}+\dfrac{3}{4}\times\dfrac{2}{9}=\dfrac{7}{12}+\dfrac{1}{6}=\dfrac{7}{12}+\dfrac{2}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)

\(b,\dfrac{8}{9}-\dfrac{4}{15}:\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{4}{15}\times\dfrac{5}{2}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)

Đáp án a là 0,75 

Đáp án b: là 0.86222222222

Giúp 

a) \(\dfrac{2}{9}+\dfrac{3}{5}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{3}{45}=\dfrac{34}{45}\)

b) \(\dfrac{5}{12}\times\dfrac{4}{5}\div4=\dfrac{1}{3}\div4=\dfrac{1}{12}\)

c) \(\dfrac{8}{9}-\dfrac{4}{15}\div\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)

a: =7/12+6/36

=7/12+2/12=9/12=3/4

b: =8/9-2/3=8/9-6/9=2/9

c: \(=\dfrac{7\cdot2+5\cdot3}{18}\cdot\dfrac{3}{5}=\dfrac{29}{18}\cdot\dfrac{3}{5}=\dfrac{87}{90}=\dfrac{29}{30}\)

a) \(\dfrac{7}{12}+\dfrac{3}{4}\times\dfrac{2}{9}=\dfrac{7}{12}+\dfrac{6}{36}=\dfrac{7}{12}+\dfrac{2}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)

b) \(\dfrac{8}{9}-\dfrac{4}{15}:\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{4}{15}\times\dfrac{5}{2}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)

c) \(\left(\dfrac{7}{9}+\dfrac{5}{6}\right)\times\dfrac{3}{5}=\dfrac{29}{18}\times\dfrac{3}{5}=\dfrac{87}{90}=\dfrac{29}{30}\)

cái gì mà hỏi dài thế cụ ?

a: 7/8<8/9<9/10<10/11<11/12

b: 4/5<5/6<6/7<7/8

c: 1/3<3/5<7/9<9/11<11/13

mấy câu sau đâu?

`5/3 xx 7/4 + 5/3 xx 5/4`

`=5/3 xx (7/4 + 5/4)`

`=5/3 xx 12/4

`=5/3 xx 3`

`=5`

( 7/4+5/4) x 5/3= 12/4 x 5/3 = 3 x 5/3= 5

\(=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=1+1=2\)

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