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ND
0
H
8 tháng 2 2023
`5`
`a, -7/21 +(1+1/3)`
`=-7/21 + ( 3/3 + 1/3)`
`=-7/21+ 4/3`
`=-7/21+ 28/21`
`= 21/21`
`=1`
`b, 2/15 + ( 5/9 + (-6)/9)`
`= 2/15 + (-1/9)`
`= 1/45`
`c, (9-1/5+3/12) +(-3/4)`
`= ( 45/5-1/5 + 3/12)+(-3/4)`
`= ( 44/5 + 3/12)+(-3/4)`
`= 9,05 +(-0,75)`
`=8,3`
`6`
`x+7/8 =13/12`
`=>x= 13/12 -7/8`
`=>x=5/24`
`-------`
`-(-6)/12 -x=9/48`
`=> 6/12 -x=9/48`
`=>x= 6/12-9/48`
`=>x=5/16`
`---------`
`x+4/6 =5/25 -(-7)/15`
`=>x+4/6 =1/5 + 7/15`
`=> x+ 4/6=10/15`
`=>x=10/15 -4/6`
`=>x=0`
`----------`
`x+4/5 = 6/20 -(-7)/3`
`=>x+4/5 = 6/20 +7/3`
`=>x+4/5 = 79/30`
`=>x=79/30 -4/5`
`=>x= 79/30-24/30`
`=>x= 55/30`
`=>x= 11/6`
VN
8 tháng 2 2023
\(5)\)
\(A=\dfrac{-7}{21}+\left(1+\dfrac{1}{3}\right)\)
\(A=\dfrac{-7}{21}+\dfrac{4}{3}\)
\(A=\dfrac{-7}{21}+\dfrac{28}{21}\)
\(A=1\)
\(--------------\)
\(B=\dfrac{2}{15}+\left(\dfrac{5}{9}+\dfrac{-6}{9}\right)\)
\(B=\dfrac{2}{15}+\dfrac{-1}{9}\)
\(B=\dfrac{18}{135}+\dfrac{-15}{135}\)
\(B=\dfrac{1}{45}\)
\(------------\)
\(C=9-\dfrac{1}{5}+\dfrac{3}{12}+\dfrac{-3}{4}\)
\(C=\dfrac{44}{5}+\dfrac{3}{12}+\dfrac{-3}{4}\)
\(C=\dfrac{528}{60}+\dfrac{15}{60}+\dfrac{-3}{4}\)
\(C=\dfrac{181}{20}+\dfrac{-3}{4}\)
\(C=\dfrac{181}{20}+\dfrac{-15}{20}\)
\(C=\dfrac{83}{10}\)
\(6)\)
\(a)\) \(x+\dfrac{7}{8}=\dfrac{13}{12}\)
\(x=\dfrac{13}{12}-\dfrac{7}{8}\)
\(x=\dfrac{104}{96}-\dfrac{84}{96}\)
\(x=\dfrac{5}{24}\)
\(b)\) \(\dfrac{-6}{12}-x=\dfrac{9}{48}\)
\(\dfrac{-1}{2}-x=\dfrac{3}{16}\)
\(x=\dfrac{-1}{2}-\dfrac{3}{16}\)
\(x=\dfrac{-8}{16}-\dfrac{3}{16}\)
\(x=\dfrac{-11}{16}\)
\(c)\) \(x+\dfrac{4}{6}=\dfrac{5}{25}-\left(-\dfrac{7}{15}\right)\)
\(x+\dfrac{4}{6}=\dfrac{5}{25}+\dfrac{7}{15}\)
\(x+\dfrac{4}{6}=\dfrac{75}{375}+\dfrac{105}{375}\)
\(x+\dfrac{4}{6}=\dfrac{12}{25}\)
\(x=\dfrac{12}{25}-\dfrac{4}{6}\)
\(x=\dfrac{72}{150}-\dfrac{100}{150}\)
\(x=\dfrac{-14}{75}\)
\(d)\) \(x+\dfrac{4}{5}=\dfrac{6}{20}-\left(-\dfrac{7}{3}\right)\)
\(x+\dfrac{4}{5}=\dfrac{6}{20}+\dfrac{7}{3}\)
\(x+\dfrac{4}{5}=\dfrac{18}{60}+\dfrac{140}{60}\)
\(x+\dfrac{4}{5}=\dfrac{79}{30}\)
\(x=\dfrac{79}{30}-\dfrac{4}{5}\)
\(x=\dfrac{79}{30}-\dfrac{24}{30}\)
\(x=\dfrac{11}{6}\)
9 tháng 10 2018
1. a) 4.415.8.25.125
= (4.25). (8.125).415
= 100.1000.415
= 100000.415
= 41500000
b) 2.31.12+4.42.6+8.27.3
= (2.31.12)+(4.42.6)+(8.27.3)
= (2.12).31+(4.6).42+(8.3).27
= 24.31+24.42+24.27
= 24 (31+42+27)
= 24.100
= 2400
B
3
2 tháng 4 2018
a,\(\frac{5}{6}:\frac{-7}{12}\) b, \(\frac{-21}{24}:\frac{-14}{8}\)
d,\(\frac{4}{5}:\frac{-8}{15}\)e,\(\frac{3}{5}+\frac{-7}{4}\)
g,\(\frac{5}{12}-\frac{-7}{12}\)h,\(\frac{-15}{16}.\frac{8}{-25}\)
22 tháng 8 2020
a) \(\frac{25}{9}-\frac{12}{13}x=\frac{7}{9}\)
=> \(\frac{12}{13}x=\frac{25}{9}-\frac{7}{9}=\frac{18}{9}=2\)
=> \(x=2:\frac{12}{13}=2\cdot\frac{13}{12}=\frac{13}{6}\)
b) \(x:\frac{13}{3}=-2,5\)
=> \(x:\frac{13}{3}=-\frac{5}{2}\)
=> \(x=\left(-\frac{5}{2}\right)\cdot\frac{13}{3}=-\frac{65}{6}\)
c) \(\frac{x}{3}-\frac{1}{4}=-\frac{5}{6}\)
=> \(\frac{4x-3}{12}=-\frac{10}{12}\)
=> 4x - 3 = -10
=> 4x = -10 + 3 = -7
=> x = -7/4
Bài 2 :
\(A=a\cdot\frac{1}{3}+a\cdot\frac{1}{4}-a\cdot\frac{1}{6}=a\left(\frac{1}{3}+\frac{1}{4}-\frac{1}{6}\right)=a\cdot\frac{5}{12}\)
Thay a = -3/5 vào biểu thức ta có : \(A=\left(-\frac{3}{5}\right)\cdot\frac{5}{12}=\frac{-3}{12}=\frac{-1}{4}\)
\(B=b\cdot\frac{5}{6}+b\cdot\frac{3}{4}-b\cdot\frac{1}{2}=b\left(\frac{5}{6}+\frac{3}{4}-\frac{1}{2}\right)=b\cdot\frac{13}{12}\)
Thay b = 12/13 vào ta được kết quả là 1
NH
22 tháng 8 2020
a ) \(\frac{25}{9}-\frac{12}{13}\cdot x=\frac{7}{9}\)
\(\Rightarrow\frac{12}{13}\cdot x=\frac{25}{9}-\frac{7}{9}=\frac{18}{9}=2\)
\(\Rightarrow x=2\div\frac{12}{13}=2\cdot\frac{13}{12}=\frac{13}{6}\)
Vậy ...
b ) \(x\div\frac{13}{3}=-\frac{5}{2}\)
\(\Rightarrow x\div\frac{13}{3}=-\frac{5}{2}\)
\(\Rightarrow x=\left(-\frac{5}{2}\right)\cdot\frac{13}{3}=-\frac{65}{6}\)
Vậy ..
c ) \(\frac{x}{3}-\frac{1}{4}=-\frac{5}{6}\)
\(\Rightarrow\frac{4x-3}{12}=-\frac{10}{12}\)
\(\Rightarrow4x-3=-10\)
\(\Rightarrow4x=-10+3=-7\)
\(\Rightarrow x=-\frac{7}{4}\)
Vậy ....
TL
2
10 tháng 2 2018
\(\frac{2}{3}+\frac{1}{3}.\left(-\frac{4}{5}+\frac{5}{6}\right):\frac{7}{12}=\frac{24}{35}\)
Xin lỗi mk ko giải dài đước
đúng đó
10 tháng 2 2018
= 2/3 + 1/3.1/30 : 7/12
= 2/3 + 1/90 : 7/12
= 2/3 + 2/105
= 24/35
Tk mk nha
AH
28 tháng 4 2017
A = - 2 / 5 + ( - 2 / 5 + 2 )
A = - 2 / 5 + 8 / 5
A = 6 / 5
B = ( - 5 / 24 + 0, 75 + 7 / 12 ) : - 17/8
B = 9 / 8 : - 17/8
B = -9 / 17
C = 3 / 7 + ( - 1 / 5 + - 3 / 7 )
C = 3 / 7 - 1 / 5 - 3 / 7
C = - 1 / 5
D = ( 6 - 14 / 5 ) . 25 / 8 - 8 / 5 : 1 / 4
D = 16 / 5 . 25 / 8 - 8 / 5 . 4
D = 10 - 6 , 4
D = 3,6
28 tháng 4 2017
\(A=-\frac{2}{5}+\left[\left(-\frac{2}{5}\right)+2\right]=\left[\left(-\frac{2}{5}\right)+\left(-\frac{2}{5}\right)\right]+2=\left(-\frac{4}{5}\right)+2=\left(-\frac{4}{5}\right)+\frac{10}{5}=\frac{6}{5}\)\(\frac{10}{5}=\frac{6}{5}\)
\(B=\left[\left(-\frac{5}{24}\right)+0,75+\frac{7}{12}\right]:\left(\frac{-17}{8}\right)\)\(=\left[\left(-\frac{5}{24}\right)+\frac{3}{4}+\frac{7}{12}\right].\frac{-8}{17}\)
\(=\left[\left(-\frac{5}{24}\right)+\frac{18}{24}+\frac{14}{24}\right].\frac{-8}{17}\)\(=\frac{27}{24}.\frac{-8}{17}=\frac{9}{8}.\frac{-8}{17}=\frac{9.\left(-8\right)}{8.17}=\frac{-9}{17}\)
\(C=\frac{3}{7}+\left[\left(-\frac{1}{5}\right)+\left(-\frac{3}{7}\right)\right]=\left[\frac{3}{7}+\left(-\frac{3}{7}\right)\right]+\left(-\frac{1}{5}\right)=-\frac{1}{5}\)
\(D=\left(6-\frac{14}{5}\right).\frac{25}{8}-\frac{8}{5}:\frac{1}{4}=\left(\frac{30}{5}-\frac{14}{5}\right).\frac{25}{8}-\frac{8}{5}.4\)
\(=\frac{16}{5}.\frac{25}{8}-\frac{32}{5}=\frac{16.25}{5.8}-\frac{32}{5}=10-\frac{32}{5}\)\(=\frac{50}{5}-\frac{32}{5}=\frac{18}{5}\)