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3 tháng 3

`(x+4/5) (1/3 - x) = 0`

`=> x+4/5 = 0` hoặc `1/3 - x = 0`

`=> x = -4/5` hoặc `x = 1/3`

Vậy ...

24 tháng 8 2019

Hello bạn, mk cx tên Mai nek.

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

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

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

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

\(\Rightarrow x+1=-1\)

\(\Rightarrow x=-1-1\)

\(\Rightarrow x=-2\)

24 tháng 8 2019

\(\left(\frac{2}{7}\times x+1\right)\times\left(3-\frac{1}{2}\times x\right)=0\)

\(TH1:\frac{2}{7}\times x+1=0\)

\(\frac{2}{7}\times x=-1\)

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

\(TH2:3-\frac{1}{2}\times x=0\)

\(\frac{1}{2}\times x=3\)

\(x=\frac{3}{2}\)

Vậy \(x\in\left\{\frac{3}{2};-\frac{2}{7}\right\}\)

14 tháng 1 2018

a,=> 3x-6-5=2x+6

=>3x-11-2x=6

=>x=6+11=15

b,=>(x+5)(x-2)(x+2)=0

Trường hợp 1

x+5=0

=>x=-5

TH2

=>x-2=0

=>x=2

TH3

=>x+2=0

=>x=-2

c,CMTT câu b

d, -1=<x=<4

e,3=<x=<8

16 tháng 7 2018

a) 3x - 2 = 0    =>   3x = 2    => x = 2/3

b) 2x - 1 = 0     =>  2x = 1      =>  x = 1/2

c) 5 ( 4+2x) = 8+5x

<=> 20 + 10x = 8 + 5x

<=> 10x - 5x = 8 - 20

<=>  5x  =  -12

x = -12/5

d) \(\frac{1}{2}+\frac{3}{4}x=6-\frac{4}{5}x\)

\(\frac{3}{4}x+\frac{4}{5}x=6-\frac{1}{2}\)

\(\frac{31}{20}x=\frac{11}{2}\)

\(x=\frac{11}{2}:\frac{31}{20}=\frac{110}{31}\)

e) 3 + 2x = 4 - 8x

<=> 2x + 8x = 4 - 3

10 x = 1

x = 1/10

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

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

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

\(x=-4-5=1\)

Vậy ......

16 tháng 7 2018

a, 3x - 2 = 0

=> 3x = 2

=> x = 2/3

vậy_

c: \(\left|\dfrac{7}{5}x+\dfrac{2}{3}\right|=\left|\dfrac{4}{3}x-\dfrac{1}{4}\right|\)

=>7/5x+2/3=4/3x-1/4 hoặc 7/5x+2/3=1/4-4/3x

=>1/15x=-11/12 hoặc 41/15x=-5/12

=>x=-55/4 hoặc x=-25/164

d: |7/8x+5/6|=|1/2x+5|

=>|42x+40|=|24x+240|

=>42x+40=24x+240 hoặc 42x+40=-24x-240

=>18x=200 hoặc 66x=-280

=>x=100/9 hoặc x=-140/33

8 tháng 8 2018

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

\(\Rightarrow\left|2x\right|=-2x\)

\(\Rightarrow2x\le0\)

\(\Rightarrow x\le0\)

Vậy \(x\le0\)

\(\left(x-1\right).\left(x+2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-1=0\\x+2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\\x=-2\end{cases}}}\)

Vậy \(\orbr{\begin{cases}x=1\\x=-2\end{cases}}\)

\(\left|x-3\right|+x-3=0\)

\(\left|x-3\right|=-x+3\)

\(\left|x-3\right|=-\left(x-3\right)\)

\(\Rightarrow x-3\le0\)

\(\Rightarrow x\le3\)

Vậy \(x\le3\)

\(\left(x+1\right)^3=\left(x+1\right)^5\)

\(\left(x+1\right)^5-\left(x+1\right)^3=0\)

\(\left(x+1\right)^3.\left[\left(x+1\right)^2-1\right]=0\)

\(\orbr{\begin{cases}\left(x+1\right)^3=0\\\left(x+1\right)^2-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-1\\x=0\end{cases}}}\)hoặc \(x=-2\)

Vậy \(x\in\left\{-1;0;-2\right\}\)

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

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

\(\Rightarrow x-2=2^3\)

\(x=8+2\)

\(x=10\)

Vậy \(x=10\)

Câu 6 tương tự câu 4

Tham khảo nhé~

P/S: nên chia nhỏ đăng thành nhiều bài khác nhau

2 tháng 5 2017

a) \(\left(2x-3\right)\left(6-2x\right)=0\)

\(\circledast\)TH1: \(2x-3=0\\ 2x=0+3\\ 2x=3\\ x=\dfrac{3}{2}\)

\(\circledast\)TH2: \(6-2x=0\\ 2x=6-0\\ 2x=6\\ x=\dfrac{6}{2}=3\)

Vậy \(x\in\left\{\dfrac{3}{2};3\right\}\).

b) \(\dfrac{1}{3}x+\dfrac{2}{5}\left(x-1\right)=0\)

\(\dfrac{1}{3}x=0-\dfrac{2}{5}\left(x-1\right)\)

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

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

\(-\dfrac{11}{15}=-x\left(x-1\right)\)

\(\Rightarrow x=1.491631652\)

Vậy \(x=1.491631652\)

c) \(\left(3x-1\right)\left(-\dfrac{1}{2}x+5\right)=0\)

\(\circledast\)TH1: \(3x-1=0\\ 3x=0+1\\ 3x=1\\ x=\dfrac{1}{3}\)

\(\circledast\)TH2: \(-\dfrac{1}{2}x+5=0\\ -\dfrac{1}{2}x=0-5\\ -\dfrac{1}{2}x=-5\\ x=-5:-\dfrac{1}{2}\\ x=10\)

Vậy \(x\in\left\{\dfrac{1}{3};10\right\}\).

d) \(\dfrac{x}{5}=\dfrac{2}{3}\\ x=\dfrac{5\cdot2}{3}\\ x=\dfrac{10}{3}\)

Vậy \(x=\dfrac{10}{3}\).

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

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

\(\dfrac{x}{3}=\dfrac{7}{10}\)

\(x=\dfrac{3\cdot7}{10}\)

\(x=\dfrac{21}{10}\)

Vậy \(x=\dfrac{21}{10}\).

f) \(\dfrac{x}{5}-\dfrac{1}{2}=\dfrac{6}{10}\)

\(\dfrac{x}{5}=\dfrac{6}{10}+\dfrac{1}{2}\)

\(\dfrac{x}{5}=\dfrac{11}{10}\)

\(x=\dfrac{5\cdot11}{10}\)

\(x=\dfrac{55}{10}=\dfrac{11}{2}\)

Vậy \(x=\dfrac{11}{2}\).

g) \(\dfrac{x+3}{15}=\dfrac{1}{3}\\ x+3=\dfrac{15}{3}=5\\ x=5-3\\ x=2\)

Vậy \(x=2\).

h) \(\dfrac{x-12}{4}=\dfrac{1}{2}\\ x-12=\dfrac{4}{2}=2\\ x=2+12\\ x=14\)

Vậy \(x=14\).

15 tháng 7 2018

\(\left(\frac{3}{4}.x-\frac{9}{16}\right).\left(\frac{1}{3}+\frac{-3}{5}:x\right)=0\)

<=> \(\hept{\begin{cases}\frac{3}{4}.x-\frac{9}{16}=0\\\frac{1}{3}-\frac{3}{5}.\frac{1}{x}=0\end{cases}}\)

<=> \(\hept{\begin{cases}x=\frac{3}{4}\\\frac{3}{5x}=\frac{1}{3}\end{cases}}\)

<=> \(\hept{\begin{cases}x=\frac{3}{4}\\x=\frac{9}{5}\end{cases}}\)

\(\left(x-\frac{1}{3}\right)\left(\frac{2}{5}+x\right)>0\)

<=> \(\hept{\begin{cases}x-\frac{1}{3}>0\\x+\frac{2}{5}>0\end{cases}}\)hoặc \(\hept{\begin{cases}x-\frac{1}{3}< 0\\x+\frac{2}{5}< 0\end{cases}}\)

<=> \(\hept{\begin{cases}x>\frac{1}{3}\\x>\frac{-2}{5}\end{cases}}\)hoặc \(\hept{\begin{cases}x< \frac{1}{3}\\x< \frac{-2}{5}\end{cases}}\)

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

câu c tương tự nha

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