Đề: Tính thuận tiện
a) 7,2 x 94,3 + 7,2 x 4,7 + 7,2
b) \(\dfrac{7}{9}X\dfrac{2}{3}+\dfrac{7}{9}X\dfrac{1}{3}\)
K
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O
3 tháng 5 2022
\(\dfrac{9}{5}+\dfrac{5}{7}+\dfrac{7}{5}+\dfrac{3}{7}=\left(\dfrac{9}{5}+\dfrac{7}{5}\right)+\left(\dfrac{5}{7}+\dfrac{3}{7}\right)=\dfrac{16}{5}+\dfrac{8}{7}=\dfrac{112}{35}+\dfrac{40}{35}=\dfrac{152}{35}\)
\(\dfrac{1}{2}\times\dfrac{45}{33}\times\dfrac{1}{9}\times\dfrac{11}{6}=\dfrac{1}{2}\times\dfrac{15}{11}\times\dfrac{1}{9}\times\dfrac{11}{6}=\left(\dfrac{1}{2}\times\dfrac{1}{9}\right)\times\left(\dfrac{15}{11}\times\dfrac{11}{6}\right)=\dfrac{1}{18}\times\dfrac{15}{6}=\dfrac{5}{36}\)
12 tháng 11 2022
60x [7/12+4/15]
60x153/180
=9180/180
b 1/2x2/3x3/4x4/5x5/6x6/7x7/8x8/9=40320/4032
6 tháng 7 2023
a: Sửa đề; \(A=\dfrac{7.2:2\cdot28.6+1.43\cdot2\cdot64}{1+3+5+7+...+49-339}\)
\(=\dfrac{3.6\cdot28.6+2.86\cdot64}{1+3+5+...+49-339}\)
\(=\dfrac{2.86\left(64+36\right)}{25^2-339}=\dfrac{286}{286}=1\)
b: =>2(x+7/8)=6*13/4=78/4=39/2
=>x+7/8=39/4
=>x=71/8
NH
10 tháng 4 2023
`3+4/9xx7/25xx27/12xx3 4/7-7/25`
`=3+4/9xx7/25xx27/12xx25/7-7/25`
`=3+7/25xx25/7xx4/9xx27/12-7/25`
`=3+4/9xx9/4xx1-7/25`
`=3+1xx1-7/25`
`=3+1-7/25`
`=75/25+25/25-7/25`
`=93/25`
S
10 tháng 4 2023
\(M=3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{27}{12}\times3\dfrac{4}{7}-\dfrac{7}{25}\)
\(=3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{27}{12}\times\dfrac{25}{7}-\dfrac{7}{25}\)
\(=3+\left(\dfrac{4}{9}\times\dfrac{27}{12}\right)\times\left(\dfrac{7}{25}\times\dfrac{25}{7}\right)-\dfrac{7}{25}\)
\(=3+\left(\dfrac{4\times3\times9}{9\times3\times4}\right)\times1-\dfrac{7}{25}\)
\(=3+1\times1-\dfrac{7}{25}\)
\(=3+1-\dfrac{7}{25}\)
\(=4-\dfrac{7}{25}\)
\(=\dfrac{100}{25}-\dfrac{7}{25}\)
\(=\dfrac{93}{25}\)
12 tháng 11 2021
a) \(\Leftrightarrow\dfrac{3}{2}:x=\dfrac{1}{2}\\ \Leftrightarrow x=\dfrac{3}{2}:\dfrac{1}{2}\\ \Leftrightarrow x=3\)
b) \(\Leftrightarrow x=\dfrac{7}{9}-\dfrac{2}{3}\\ \Leftrightarrow x=\dfrac{1}{9}\)
c) \(\Leftrightarrow x=\dfrac{8}{7}:\dfrac{6}{7}\\ \Leftrightarrow x=\dfrac{4}{3}\)
d) \(\Leftrightarrow x=\dfrac{9}{5}-\dfrac{3}{7}\\ \Leftrightarrow x=\dfrac{48}{35}\)
15 tháng 11 2021
a) x = 3
b) x = \(\dfrac{1}{9}\)
c) x = \(\dfrac{4}{3}\)
d)\(\dfrac{48}{35}\)
H
16 tháng 10 2023
`(6/11 +5/11) xx 3/7`
`= 11/11xx 3/7`
`=1xx3/7`
`=3/7`
__
`3/5 xx 7/9 - 3/5 xx 2/9`
`= 3/5 xx (7/9-2/9)`
`= 3/5 xx 5/9`
`= 15/45`
`= 1/3`
__
`(6/7 -4/7):2/5`
`= 2/7 : 2/5`
`= 2/7 xx 5/2`
`= 10/14`
`= 5/7`
H9
HT.Phong (9A5)
CTVHS
16 tháng 10 2023
\(\left(\dfrac{6}{11}+\dfrac{5}{11}\right)\times\dfrac{3}{7}\)
\(=\dfrac{11}{11}\times\dfrac{3}{7}\\ =1\times\dfrac{3}{7}=\dfrac{3}{7}\)
_____
\(\dfrac{3}{5}\times\dfrac{7}{9}-\dfrac{3}{5}\times\dfrac{2}{9}\\ =\dfrac{3}{5}\times\left(\dfrac{7}{9}-\dfrac{2}{9}\right)\\ =\dfrac{3}{5}\times\dfrac{5}{9}\\ =\dfrac{3}{9}\\ =\dfrac{1}{3}\)
_________
\(\left(\dfrac{6}{7}-\dfrac{4}{7}\right):\dfrac{2}{5}\\ =\dfrac{2}{7}\times\dfrac{5}{2}\\ =\dfrac{10}{14}\\ =\dfrac{5}{7}\)
a) 7,2 x 94,3 + 7,2 x 4,7 + 7,2
=7,2 x(94,3+4,7+1)
=7,2x100
=720
b)\(\dfrac{7}{9}\times\dfrac{2}{3}+\dfrac{7}{9}\times\dfrac{1}{3}=\dfrac{7}{9}\times\left(\dfrac{2}{3}+\dfrac{1}{3}\right)=\dfrac{7}{9}\times1=\dfrac{7}{9}\)