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29 tháng 9 2024

`a, -3x - 3/4 = 6/5`

`=> -3x = 6/5 + 3/4`

`=> -3x = 39/20`

`=> x = 39/20 : -3`

`=> x = -13/20`

Vậy `x =-13/20`

`b, 1/7 - 3/5x = 3/5`

`=> 3/5x = 1/7 - 3/5`

`=> 3/5x = -16/35`

`=> x = -16/35 : 3/5`

`=> x = -16/21`

Vậy `x =-16/21`

 

a: \(-3x-\dfrac{3}{4}=\dfrac{6}{5}\)

=>\(-3x=\dfrac{3}{4}+\dfrac{6}{5}=\dfrac{15}{20}+\dfrac{24}{20}=\dfrac{39}{20}\)

=>\(x=\dfrac{39}{20}:\left(-3\right)=-\dfrac{13}{20}\)

b: \(\dfrac{1}{7}-\dfrac{3}{5}x=\dfrac{3}{5}\)

=>\(\dfrac{3}{5}x=\dfrac{1}{7}-\dfrac{3}{5}=\dfrac{5}{35}-\dfrac{21}{35}=-\dfrac{16}{35}\)

=>\(x=-\dfrac{16}{35}:\dfrac{3}{5}=-\dfrac{16}{35}\cdot\dfrac{5}{3}=\dfrac{-16}{21}\)

c: \(\dfrac{3}{7}-\dfrac{1}{2}x=\dfrac{5}{3}\)

=>\(\dfrac{1}{2}x=\dfrac{3}{7}-\dfrac{5}{3}=\dfrac{9}{21}-\dfrac{35}{21}=-\dfrac{26}{21}\)

=>\(x=-\dfrac{26}{21}\cdot2=-\dfrac{52}{21}\)

d: \(-\dfrac{2}{3}x+2=\dfrac{3}{4}\)

=>\(-\dfrac{2}{3}x=\dfrac{3}{4}-2=-\dfrac{5}{4}\)

=>\(x=\dfrac{5}{4}:\dfrac{2}{3}=\dfrac{5}{4}\cdot\dfrac{3}{2}=\dfrac{15}{8}\)

20 tháng 9 2020

ngu thế à bạn

16 tháng 11 2023

a) 1/4(x-3)+2=1/5

1/4.(x-3) = 1/5-2

1/4.(x-3) = -9/5

x-3 = (-9/5):1/4

x-3 = -36/5

x = -36/5+3

x= -21/5

28 tháng 8 2018

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

<=> \(\frac{2}{3}x-\frac{2}{3}-x-\frac{3}{4}=1\)

<=> \(-\frac{1}{3}x-\frac{17}{12}=1\)

<=> \(-\frac{1}{3}x=\frac{29}{12}\)

<=> \(x=-\frac{29}{4}\)

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

<=> \(\frac{5}{6}x+\frac{5}{3}-x-\frac{1}{2}=\frac{1}{3}\)

<=> \(-\frac{1}{6}x+\frac{7}{6}=\frac{1}{3}\)

<=> \(-\frac{1}{6}x=-\frac{5}{6}\)

<=> \(x=5\)

học tốt

8 tháng 9 2019

a) -4/5 + 5/2x = -3/10

5/2x = -3/10 + 4/5

5/2x = 1/5

5/2x = 1/2

x = 1/2 : 5/2

x = 1/5

b) 4/3 + 5/8 : x = 1/12

5/8x = 1/12 - 4/3

5/8x = -5/4

5 = -5/4.8x

5 = -10x

5/-10 = x

-1/2 = x

x = -1/2

c) (x - 1/3)(x - 2/5) = 0

x - 1/3 = 0 hoặc x - 2/5 = 0

x = 0 + 1/3         x = 0 + 2/5

x = 1/3               x = 2/5

8 tháng 9 2019

Bạn làm hộ mình bài 2 đc k ạ ?

1 tháng 12 2019

\(\left(\frac{2}{5}\right)^2+5\frac{1}{2}:\left(4,5-2\right)-0,2\)

\(=\frac{4}{25}+\frac{11}{2}:\frac{5}{2}-\frac{1}{5}\)

\(=\frac{4}{25}+\frac{11}{2}.\frac{2}{5}-\frac{1}{5}\)

\(=\frac{4}{25}+\frac{11}{5}-\frac{1}{5}\)

\(=\frac{4}{25}+\frac{55}{25}-\frac{5}{25}\)

\(=\frac{54}{25}\)

a) Đề sai

b) \(\left|x+\frac{4}{5}\right|=\frac{1}{7}\)

\(\Rightarrow\orbr{\begin{cases}x+\frac{4}{5}=\frac{1}{7}\\x+\frac{4}{5}=\frac{-1}{7}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{7}-\frac{4}{5}\\x=\frac{-1}{7}-\frac{4}{5}\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{5}{35}-\frac{28}{35}\\x=\frac{-5}{35}-\frac{28}{35}\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{-23}{35}\\x=\frac{-33}{35}\end{cases}}}\)

Vậy \(x=\frac{-23}{35}\)hoặc \(x=\frac{-33}{35}\)

23 tháng 6 2018

\(a,\frac{-3}{2}-2x+\frac{3}{4}=-1\)

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

\(\frac{-3}{2}-2x=\frac{-7}{4}\)

\(2x=\frac{-7}{4}+\frac{-3}{2}\)

\(2x=\frac{-13}{4}\)

\(x=\frac{-13}{4}:2\)

\(x=\frac{-13}{4}.\frac{1}{2}\)

\(x=\frac{-13}{8}\)

17 tháng 9 2016

a)\(x+\frac{1}{3}=\frac{3}{4}\)

\(\Rightarrow x=\frac{3}{4}-\frac{1}{3}\)

\(\Rightarrow x=\frac{5}{12}\)

b)\(x-\frac{2}{5}=\frac{5}{7}\)

\(\Rightarrow x=\frac{5}{7}+\frac{2}{5}\)

\(\Rightarrow x=1\frac{4}{35}\)

c)\(-x-\frac{2}{3}=-\frac{6}{7}\)

\(\Rightarrow-x=-\frac{6}{7}+\frac{2}{3}\)

\(\Rightarrow-x=-\frac{4}{21}\)

\(\Rightarrow x=\frac{4}{21}\)

d)\(\frac{4}{7}-x=\frac{1}{3}\)

\(x=\frac{4}{7}-\frac{1}{3}\)

\(\Rightarrow x=\frac{5}{21}\)