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

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

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

=>\(\dfrac{2}{5}x=-3+\dfrac{1}{4}=\dfrac{-11}{4}\)

=>\(x=-\dfrac{11}{4}:\dfrac{2}{5}=\dfrac{-11}{4}\cdot\dfrac{5}{2}=\dfrac{-55}{8}\)

10 tháng 3

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

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

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

\(\Rightarrow\dfrac{2}{5}x-\dfrac{1}{4}=\dfrac{-3}{4}\cdot4\)

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

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

\(\Rightarrow\dfrac{2}{5}x=\dfrac{-35}{4}\)

\(\Rightarrow x=\dfrac{-11}{4}:\dfrac{2}{5}\)

\(\Rightarrow x=\dfrac{-55}{8}\)

AH
Akai Haruma
Giáo viên
14 tháng 11 2023

Lời giải:

1. $(x+2)-2=0$

$x+2=2$

$x=0$

2.

$(x+3)+1=7$

$x+3=7-1=6$

$x=6-3=3$

3.

$(3x-4)+4=12$

$3x-4+4=12$

$3x=12$

$x=12:3=4$

4.

$(5x+4)-1=13$

$5x+4=13+1=14$

$5x=14-4=10$

$x=10:5=2$

5.

$(4x-8)-3=5$

$4x-8=5+3=8$

$4x=8+8=16$

$x=16:4=4$

6.

$3+(x-5)=7$

$x-5=7-3=4$

$x=4+5=9$

7.

$8-(2x-4)=2$

$2x-4=8-2=6$

$2x=6+4=10$

$x=10:2=5$

8.

$7+(5x+2)=14$

$5x+2=14-7=7$

$5x=7-2=5$

$x=5:5=1$

9.

$5-(3x-11)=1$

$3x-11=5-1=4$

$3x=11+4=15$

$x=15:3=5$

10.

$16-(8x+2)=6$

$8x+2=16-6=10$

$8x=10-2=8$

$x=8:8=1$

a: =>x/27+1=-2/3

=>x/27=-5/3

=>x=-45

b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)

=>x=221/50

c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)

=>x=1/15-2/3=1/15-10/15=-9/15=-3/5

d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)

=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)

=>x=-37/24

e: =>-3/7x=84/45

=>x=-196/45

f: =>11/10x=-2/3

=>x=-20/33

b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)

=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)

=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)

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

=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)

=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)

=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)

d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)

=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)

=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)

=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)

19 tháng 6 2023

\(\left(x+2\right)-2=0\)

\(\Rightarrow x+2-2=0\)

\(\Rightarrow x=0\)

\(\left(x+3\right)+1=7\)

\(\Rightarrow x+3+1=7\)

\(\Rightarrow x+4=7\)

\(\Rightarrow x=3\)

\(\left(3x-4\right)+4=12\)
\(\Rightarrow3x-4+4=12\)

\(\Rightarrow3x=12\)

\(\Rightarrow x=4\)

\(\left(5x+4\right)-1=13\)

\(\Rightarrow5x+4-1=13\)

\(\Rightarrow5x+3=13\)

\(\Rightarrow5x=10\)

\(\Rightarrow x=2\)

\(\left(4x-8\right)-3=5\)

\(\Rightarrow4x-8-3=5\)

\(\Rightarrow4x-11=5\)

\(\Rightarrow4x=16\)

\(\Rightarrow x=4\)

\(8-\left(2x+4\right)=2\)

\(\Rightarrow8-2x-4=2\)

\(\Rightarrow4-2x=2\)

\(\Rightarrow2x=2\)

\(\Rightarrow x=1\)

\(7+\left(5x+2\right)=14\)

\(\Rightarrow7+5x+2=14\)

\(\Rightarrow9+5x=14\)

\(\Rightarrow5x=5\)

\(\Rightarrow x=1\)

\(5-\left(3x-11\right)=1\)

\(\Rightarrow5-3x+11=1\)

\(\Rightarrow16-3x=1\)

\(\Rightarrow3x=15\)

\(\Rightarrow x=5\)

24 tháng 7 2021

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

\(\left(\dfrac{11}{4}-\dfrac{9}{5}\right)\cdot x=1\)

\(\dfrac{19}{20}x=1\)

\(x=\dfrac{20}{19}\)

Vậy \(x=\dfrac{20}{19}\)

24 tháng 7 2021

b) \(\left(x^2-9\right)\left(3-5x\right)=0\)

TH1:

\(x^2-9=0\)

\(x^2=9\)

\(x^2=3^2=\left(-3\right)^2\)

=>\(x\in\left\{3;-3\right\}\)

TH2:

\(3-5x=0\)

\(5x=3\)

\(x=\dfrac{3}{5}\)

Vậy \(x\in\left\{3;-3;\dfrac{3}{5}\right\}\)

 

a:x=3/5-7/8=24/40-35/40=-11/40

b: =>1/3:(2x-1)=-1/6

=>2x-1=-2

=>2x=-1

=>x=-1/2

c: =>x-3/4=17/2+7/4=34/4+7/4=41/4

=>x=11

d: =>3x+2=0 hoặc 2/5x+7=0

=>x=-2/3 hoặc x=-7:2/5=-35/2

3 tháng 5 2019

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

=> ( 11/4 - 9/5 ) x = 1

=> 19/20 x = 1

=> x = 1 : 19/20

=> x = 20/19  

3 tháng 5 2019

x^2 - 9 .( 3 - 5x ) = 0

=> x^-7 . ( 3 - 5x ) = 0

=> x^-7 = 0 hoặc 3 - 5x = 0

=> Mà x^-7 = 0 => x loại

=> 3 - 5x = 0

=> 5x = 3 - 0 = 3

=> x = 3 : 5

=> x = 3/5

15 tháng 5 2017

a) Ta có: \(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)

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

\(\Rightarrow x-\frac{1}{2}=\frac{1}{2}\Rightarrow x=1\)

hoặc \(x-\frac{1}{2}=-\frac{1}{2}\Rightarrow x=-\frac{1}{2}+\frac{1}{2}=0\)

Vậy \(x\in\left\{1;0\right\}\)

b)\(20\%.x+\frac{2}{5}x=x-4\)

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

\(\Rightarrow\frac{-2}{5}x=-4\)

\(\Rightarrow x=-4:\left(-\frac{2}{5}\right)=10\)

Vậy x=10

c) 3(x+1)+4(x+3)-2(x+16) = 18

=> 3x+3+4x+12-2x-32 =18

=> (3x+4x-2x)+(3+12-32)=18

=> 5x - 17 = 18

=> 5x = 18 + 17 = 35

=> x = 35 : 5 = 7

Vậy x = 7

15 tháng 5 2017

sao3x+3 rồi 4x +12 là sao mình hk hiểu