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28 tháng 4

 - \(\dfrac{1}{9}\) \(\times\) (- \(\dfrac{3}{5}\)) + \(\dfrac{5}{-6}\) \(\times\) (- \(\dfrac{3}{5}\)) - \(\dfrac{7}{2}\) \(\times\) \(\dfrac{3}{5}\)

= ( - \(\dfrac{3}{5}\)\(\times\) (- \(\dfrac{1}{9}\)  - \(\dfrac{5}{6}\)  + \(\dfrac{7}{2}\))

= - \(\dfrac{3}{5}\) \(\times\) (- \(\dfrac{17}{18}\) + \(\dfrac{7}{2}\))

= - \(\dfrac{3}{5}\) \(\times\)  \(\dfrac{23}{9}\)

 = - \(\dfrac{23}{15}\)

16 tháng 8 2023

a) \(\dfrac{13}{20}+\dfrac{3}{5}+x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{5}{4}+x=\dfrac{5}{6}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{5}{4}\)

\(\Rightarrow x=\dfrac{-5}{12}\)

b) \(x+\dfrac{1}{3}=\dfrac{2}{5}-\dfrac{-1}{3}\)

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{11}{15}\)

\(\Rightarrow x=\dfrac{11}{15}-\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{2}{5}\)

c)\(\dfrac{-5}{8}-x=\dfrac{-3}{20}-\dfrac{-1}{6}\)

\(\dfrac{-5}{8}-x=\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-5}{8}-\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-77}{120}\)

d) \(\dfrac{3}{5}-x=\dfrac{1}{4}+\dfrac{7}{10}\)

\(\Rightarrow\dfrac{3}{5}-x=\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{3}{5}-\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{-7}{20}\)

e) \(\dfrac{-3}{7}-x=\dfrac{4}{5}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{-3}{7}-x=\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-3}{7}-\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-59}{105}\)

16 tháng 8 2023

g) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-13}{12}\)

29 tháng 12 2015

1. -x+20 = -(-15)-8+13

=> -x=15-8+13-20

=> -x=0

=> x=0

2. -(-10)+x=-13+(-9)+(-6)

=> 10+x=-13-9-6

=> x = -13-9-6-10

=> x = -38

3. 8-(-12)+10=-(-14)-x

=> 8+12+10=14-x

=> x = 14-8-12-10

=> x = -16

4. -(+12)+(-x)-(-3)=5-(-7)

=> -12-x+3=5+7

=> -x=5+7+12-3

=> -x=21

=> x=-21

5. 14-x+(-10)=-(-9)+(+15)

=> 14-x-10=9+15

=> -x=9+15-14+10

=> -x=20

=> x=-20

6. 12-(-17)+(-3)=-5+x

=> 12+17-3+5=x

=> x=31

7. x-(-19)-(+32)=14-(+16)

=> x+19-32=14-16

=> x=14-16+32-19

=> x=11

8. x-|-15|-|7|=-(-9)+|-5|

=> x-15-7=9+5

=> x=9+5+7+15

=> x=36

9. 15-x+17=13-(-21)

=> 15-x+17=13+21

=> -x=13+21-15-17

=> -x=2

=> x=-2

10. -|-5|-(-x)+4=3-(-25)

=> -5+x+4=3+25

=> x=3+25-4+5

=> x=29

16 tháng 8 2023

a) \(\dfrac{1}{2}-\left(x+\dfrac{1}{3}\right)=\dfrac{5}{6}\)

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{1}{2}-\dfrac{5}{6}\)

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{-1}{3}\)

\(\Rightarrow x=\dfrac{-1}{3}-\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{-2}{3}\)

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

\(\Rightarrow x+\dfrac{1}{2}=\dfrac{3}{4}-\dfrac{4}{5}\)

\(\Rightarrow x+\dfrac{1}{2}=\dfrac{-1}{20}\)

\(\Rightarrow x=\dfrac{-1}{20}-\dfrac{1}{2}\)

\(\Rightarrow x=\dfrac{-11}{20}\)

16 tháng 8 2023

c) \(\dfrac{3}{35}-\left(\dfrac{3}{5}+x\right)=\dfrac{2}{7}\)

\(\Rightarrow\dfrac{3}{5}+x=\dfrac{3}{35}-\dfrac{2}{7}\)

\(\Rightarrow\dfrac{3}{5}+x=\dfrac{-1}{5}\)

\(\Rightarrow x=\dfrac{-1}{5}-\dfrac{3}{5}\)

\(\Rightarrow x=\dfrac{-4}{5}\)

d)\(\dfrac{2}{3}.x=\dfrac{4}{27}\)

\(\Rightarrow x=\dfrac{4}{27}:\dfrac{2}{3}\)

\(\Rightarrow x=\dfrac{2}{9}\)

e) \(\dfrac{-3}{5}.x=\dfrac{21}{10}\)

\(\Rightarrow x=\dfrac{21}{10}:\dfrac{-3}{5}\)

\(\Rightarrow x=\dfrac{-7}{2}\)

8 tháng 10 2021

a) \(\dfrac{x-3}{x+5}=\dfrac{5}{7}\)

\(7\left(x-3\right)=5\left(x+5\right)\)

\(7x-21=5x+25\)

\(7x-21-5x-25=0\)

\(2x-46=0\)

\(2x=46\)

\(x=23\)

8 tháng 10 2021

giúp mik phần b nha đc ko ???

1 tháng 8 2020

\(\frac{5}{7}+y\times\frac{1}{2}=\frac{8}{7}:\frac{3}{2}\)

=> \(\frac{5}{7}+y\times\frac{1}{2}=\frac{8}{7}\times\frac{2}{3}\)

=> \(\frac{5}{7}+y\times\frac{1}{2}=\frac{16}{21}\)

=> \(y\times\frac{1}{2}=\frac{16}{21}-\frac{5}{7}=\frac{1}{21}\)

=> \(y=\frac{1}{21}:\frac{1}{2}=\frac{1}{21}\cdot2=\frac{2}{21}\)

5/7 + Y x 1/2 = 8/7 : 3/2

=> 5/7 + Y x 1/2 = 16/21

=> Y x 1/2 = 16/21 - 5/7

=> Y x 1/2 = 1/21

=> Y = 1/21 : 1/2 

=> Y = 2/21

Hok tốt ^^

30 tháng 3 2020

1/x-1+2/x-2+3/x-3=6/x-6

17 tháng 8 2023

NHANH NHANH GIÚP MÌNH VỚI NHÉ MÌNH ĐANG CẦN GẤP 

 

17 tháng 8 2023

Bài 7:

a, \(x\) = \(\dfrac{1}{5}\) + \(\dfrac{2}{11}\)

    \(x\) = \(\dfrac{11}{55}\) + \(\dfrac{10}{55}\)

     \(x=\dfrac{21}{55}\)

b, \(\dfrac{x}{15}\) = \(\dfrac{3}{5}\) - \(\dfrac{2}{3}\)

    \(\dfrac{x}{15}\) = \(\dfrac{9}{15}\) - \(\dfrac{10}{15}\)

      \(\dfrac{x}{15}\) = \(\dfrac{1}{15}\)

      \(x\) = 1

c, \(\dfrac{11}{8}\) + \(\dfrac{13}{6}\)\(\dfrac{85}{x}\)

     \(\dfrac{33}{24}\) + \(\dfrac{52}{24}\) = \(\dfrac{85}{x}\)

       \(\dfrac{85}{24}\) = \(\dfrac{85}{x}\)

        24 = \(x\)

28 tháng 12 2015

Bạn ơi bạn làm đc bao nhiêu thì làm phụ mình nhé 

4 tháng 6 2021

bài1

a, 

5 - 7 + 3 +(-8)

= -2 + 3 + ( - 8)

=     1    + (-8)= -7