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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
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Cách 1 : ( 7/5 x2 ) + ( 4/3 x 2 )
= 14/5 + 8/3
= 82/15
Cách 2 : ( 7/5 +4/3) x 2
= 41/15 x 2
= 82/15
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`(1/3 + 1/5) xx 1/4`
`= ( 5/15 + 3/15) xx 1/4`
`= 8/15 xx 1/4`
`= 8/60`
`= 2/15`
__
`(1/3 + 1/5) xx 1/4`
`= 1/3 xx 1/4 + 1/5 xx 1/4`
`= 1/12 +1/20`
`=2/15`
\(C_1:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{4}\times\dfrac{1}{3}+\dfrac{1}{4}\times\dfrac{1}{5}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{2}{15}\)
\(C_2:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8\times1}{15\times4}=\dfrac{8}{60}=\dfrac{2}{15}\)
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a: \(=\dfrac{3\cdot2+5}{10}\cdot\dfrac{4}{5}=\dfrac{11}{10}\cdot\dfrac{4}{5}=\dfrac{44}{50}=\dfrac{22}{25}\)
b: \(=\dfrac{2}{5}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\)
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a: \(=\dfrac{2}{3}\cdot\dfrac{4}{5}\cdot\dfrac{5}{6}=\dfrac{2}{3}\cdot\dfrac{2}{3}=\dfrac{4}{9}\)
b: \(=\dfrac{5}{6}\cdot\dfrac{1}{5}=\dfrac{1}{6}\)
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a. C1: \(\dfrac{8}{15}.\dfrac{5}{6}=\dfrac{4}{9}\)
C2: \(\dfrac{2}{3}.\dfrac{4}{5}.\dfrac{5}{6}=\dfrac{2.4.5}{3.5.3.2}\)
Triệt tiêu phần giống nhau ở tử và mẫu ta có
\(=\dfrac{4}{9}\)
b. \(C1:\left(\dfrac{1}{2}+\dfrac{1}{3}\right).\dfrac{1}{5}=\dfrac{5}{6}.\dfrac{1}{5}=\dfrac{1}{6}\)
C2: \(\dfrac{1}{2}.\dfrac{1}{5}+\dfrac{1}{3}.\dfrac{1}{5}=\dfrac{1}{10}+\dfrac{1}{15}=\dfrac{1}{6}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8}{60}=\dfrac{2}{15}\)
\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{5}\times\dfrac{1}{4}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{20}{240}+\dfrac{12}{240}=\dfrac{32}{240}=\dfrac{2}{15}\)
\(b,\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{2}{5}\times\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\times1=\dfrac{2}{5}\)
\(\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{6}{35}+\dfrac{8}{35}=\dfrac{14}{35}=\dfrac{2}{5}\)
trả lời nhanh nha! trả lời trong tối hôm nay 19/3/2023 ạ
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a: \(=\dfrac{10-6}{15}\cdot\dfrac{1}{3}=\dfrac{4}{45}\)
b: \(=\dfrac{10+6}{15}\cdot\dfrac{1}{3}=\dfrac{16}{45}\)
c: \(=\dfrac{4+3}{6}\cdot\dfrac{4}{3}=\dfrac{7\cdot4}{6\cdot3}=\dfrac{28}{18}=\dfrac{14}{9}\)
d: \(=\dfrac{20-14}{35}\cdot\dfrac{9}{4}=\dfrac{6}{35}\cdot\dfrac{9}{4}=\dfrac{54}{140}=\dfrac{27}{70}\)
a (2/3 - 2/5 ) nhân 1/3
C1)
=4/15 x 1/3
= 4/45
C2)
2/3 x 1/3 - 2/5 x 1/3
= 2/9 - 2/15
= 4/45
b (2/3 + 2/5 )nhân 1/3
GIỐNG CÂU A
c (2/3 + 1/2 ) chia 3/4
C1) =7/6 : 3/4
= 14/9
C2)
2/3 : 3/4 + 1/2 : 3/4
= 8/9 + 2/3
= 14/9
d(4/7 - 2/5 ) chia 4/9
C1)
= 6/35 : 4/9
= 27/70
C2)
4/7 : 4/9 - 2/5 : 4/9
= 9/7 -9/10
= 27/70
cach 1 [1/3+2/5]*3/4
=[5/15+6/15]*3/4
=11/15*3/4
=33/60
=11/20
cach 2 :
[1/3+2/5]*3/4
=1/3*3/4+2/5*3/4
=1/4+3/10
=5/20+6/20
=11/20
kết qur=ả bằng 11/20 nhá