a) Cách 1 : (3/4 + 1/2) x 5/7

               = 5/4 x 5/7

                = 25/28

Cách 2 : (3/4 + 1/2) x 5/7

           = 3/4 x 5/7 + 1/2 x 5/7

            = 15/28 + 5/14

            = 25/28

b) Cách 1 : 5/7 x 13/21 + 2/7 x 13/21

= 65/147 + 26/147

= 13/21

Cách 2 : 5/7 x 13/21 + 2/7 x 13/21

= (5/7 + 2/7) x 13/21

= 1 x 13/21

= 13/21

câu c tự làm

8 /15 :2/3+7/15:2/3 =                                              tính bằng 2 cách nhé các bạn

Cách 1:6/8+4/8+5/7=10/8*5/7=50/56=25/28

Cách 2 :3/4*5/7+1/2*
5/7=15/28+10/28=25/28

Cái này thầy tôi đã chữa yên tâm

a) Cách 1

\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)

= \(\frac{3}{8}\)x \(2\)

= \(\frac{3}{4}\)

Cách 2

\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)

= \(\frac{3}{4}\)x \(\left(\frac{1}{2}x2\right)\)

= \(\frac{3}{4}\)x 1

= \(\frac{3}{4}\)

\(a,\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8}{60}=\dfrac{2}{15}\)

\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{5}\times\dfrac{1}{4}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{20}{240}+\dfrac{12}{240}=\dfrac{32}{240}=\dfrac{2}{15}\)

\(b,\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{2}{5}\times\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\times1=\dfrac{2}{5}\)

\(\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{6}{35}+\dfrac{8}{35}=\dfrac{14}{35}=\dfrac{2}{5}\)

trả lời nhanh nha! trả lời trong tối hôm nay 19/3/2023 ạ

C1 : `a)(1/3+1/5)xx1/4`

`=(5/15+3/15)xx1/4`

`=8/15xx1/4`

`=8/60`

`=2/15`

__

C2: `a)(1/3+1/5)xx1/4`

`=1/3xx1/4+1/5xx1/4`

`=1/12+1/20`

`=5/60+3/60`

`=8/60`

`=2/15`

_________________

C1: `b)2/5xx3/7+2/5xx4/7`

`=6/35+8/35`

`=14/35`

`=2/5`

__

C2: `b)2/5xx3/7+2/5xx4/7`

`=2/5xx(3/7+4/7)`

`=2/5xx7/7`

`=2/5xx1`

`=2/5`

\(\dfrac{4}{7}:\dfrac{4}{3}+5:\dfrac{4}{3}=\left(\dfrac{4}{7}+5\right):\dfrac{4}{3}=\dfrac{39}{7}:\dfrac{4}{3}=\dfrac{39}{7}\times\dfrac{3}{4}=\dfrac{117}{28}\)

\(\dfrac{4}{7}:\dfrac{4}{3}+5:\dfrac{4}{3}=\dfrac{3}{7}+\dfrac{15}{4}=\dfrac{12}{28}+\dfrac{105}{28}=\dfrac{117}{28}\)

\(\dfrac{3}{4}\times\dfrac{2}{5}-\dfrac{3}{4}\times\dfrac{2}{7}=\dfrac{3}{4}\times\left(\dfrac{2}{5}-\dfrac{2}{7}\right)=\dfrac{3}{4}\times\dfrac{4}{35}=\dfrac{12}{140}=\dfrac{3}{35}\)

\(\dfrac{3}{4}\times\dfrac{2}{5}-\dfrac{3}{4}\times\dfrac{2}{7}=\dfrac{3}{10}-\dfrac{3}{14}=\dfrac{42}{140}-\dfrac{30}{140}=\dfrac{12}{140}=\dfrac{3}{35}\)

\(\left(\dfrac{2}{3}-\dfrac{4}{7}\right)\times\dfrac{2}{5}=\dfrac{2}{21}\times\dfrac{2}{5}=\dfrac{4}{105}\)

\(\left(\dfrac{2}{3}-\dfrac{4}{7}\right)\times\dfrac{2}{5}=\dfrac{2}{3}\times\dfrac{2}{5}-\dfrac{4}{7}\times\dfrac{2}{5}=\dfrac{4}{15}-\dfrac{8}{35}=\dfrac{140}{525}-\dfrac{120}{525}=\dfrac{20}{525}=\dfrac{4}{105}\)

#YVA

4/7:4/3+5:4/3

= 3/7 + 15/4

=4 5/28

4/7:4/3+5:4/3

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

=4 5/28

3/4x2/5-3/4x2/7

=3/10 - 3/14

=3/35

3/4x2/5-3/4x2/7

=3/4x(2/5-2/7)

=3/35

(2/3-4/7)x2/5

=2/21x2/5

=4/105

(2/3-4/7)x2/5

=2/3x2/5-4/7x2/5

=4/105

\(=\left(\dfrac{7}{5}+\dfrac{4}{3}\right)\cdot2=\dfrac{21+20}{15}\cdot2=\dfrac{82}{15}\)

82/15

Ghi cả cách trình bày nha mọi người

\(a,\dfrac{4}{15}:\dfrac{4}{7}< x< \dfrac{2}{5}\times\dfrac{10}{3}\\ \Leftrightarrow\dfrac{7}{15}< x< \dfrac{4}{3}\\ \Leftrightarrow x=1\)

\(b,\dfrac{3}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{9}{35}+\dfrac{8}{35}=\dfrac{17}{35}\)

C!:7/5 + 4/3 + 7/5 + 4/3

=31/15+31/15

=62/15

C2:7/5 + 4/3 + 7/5 + 4/3

=7/5+4/3

=62/15

C!:7/5 + 4/3 + 7/5 + 4/3

=31/15+31/15

=62/15

C2:7/5 + 4/3 + 7/5 + 4/3

=7/5+4/3

=62/15

C!:7/5 + 4/3 + 7/5 + 4/3

=31/15+31/15

=62/15

C2:7/5 + 4/3 + 7/5 + 4/3

=7/5+4/3

=62/15