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a: =>3x=8

hay x=8/3

b: =>6-3x-x-2=0

=>-4x+4=0

hay x=1

4 tháng 1 2022

\(a,2x+x-3=5\\ \Rightarrow3x=5+3\\ \Rightarrow3x=8\\ \Rightarrow x=\dfrac{8}{3}\\ b,3\left(2-x\right)-\left(x+2\right)=0\\ \Rightarrow6-3x-x-2=0\\ \Rightarrow4-4x=0\\ \Rightarrow4x=4\\ \Rightarrow x=1\)

6 tháng 4 2022

\(a,\left|2x+2\right|+10=2x\)

*TH1 : \(\left|2x+2\right|=2x+2\Leftrightarrow2x+2>0\Leftrightarrow x>-1\)

\(\Rightarrow2x+2+10=2x\)

\(\Leftrightarrow2x-2x=-10-2\)

\(\Leftrightarrow0x=-12\left(vô\cdot lý\right)\)

*TH2 :\(\left|2x+2\right|=-2x-2\Leftrightarrow-2x-2< 0\Leftrightarrow x>-1\)

\(\Rightarrow-2x-2+10=2x\)

\(\Leftrightarrow-2x-2x=-10+2\)

\(\Leftrightarrow-4x=-8\)

\(\Leftrightarrow x=\dfrac{1}{2}\left(nhận\right)\)

Vậy \(S=\left\{\dfrac{1}{2}\right\}\)

\(b,\left|x-6\right|=\left|3-2x\right|\)

\(\Leftrightarrow\left[{}\begin{matrix}x-6=3-2x\\x-6=-3+2x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)

Vậy \(S=\left\{-3;3\right\}\)

16 tháng 2 2022

a/

\(\Leftrightarrow x^2-2x+4-4=0\\ \Leftrightarrow x\left(x-2\right)=0\)

\(\Leftrightarrow x=0;x-2=0\)

\(\Leftrightarrow x=0;x=2\)

16 tháng 2 2022

b/

\(\Leftrightarrow\left(x-3\right)\left(x+3\right)-2x\left(x-3\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(x+3-2x\right)=0\)

\(\Leftrightarrow\left(x-3\right)\left(3-x\right)=0\)

\(\Rightarrow x=3\)

13 tháng 3 2022

\(a)PT\Leftrightarrow4x^2-9-4x^2+20x+3x=0.\\ \Leftrightarrow23x=9.\\ \Leftrightarrow x=\dfrac{9}{23}.\\ b)PT\Leftrightarrow\left(2x+1\right)\left(4x-3\right)-\left(2x+1\right)\left(2x-1\right)=0.\\\Leftrightarrow\left(2x+1\right)\left(4x-3-2x+1\right)=0.\\ \Leftrightarrow\left(2x+1\right)\left(2x-2\right)=0.\\ \Leftrightarrow\left(2x+1\right)\left(x-1\right)=0. \)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-1}{2}.\\x=1.\end{matrix}\right.\)

a: \(\Leftrightarrow2x\left(x^2+2x+5\right)=0\)

=>x=0

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

\(\Leftrightarrow x^2-4x+3=2x\left(x-3\right)-2\left(x^2-1\right)\)

\(\Leftrightarrow x^2-4x+3=2x^2-6x-2x^2+2=-6x+2\)

\(\Leftrightarrow x^2+2x+1=0\)

=>x=-1(nhận)

22 tháng 2 2022

\(a,2x^3+4x^2+10x=0\\ \Leftrightarrow2x\left(x^2+2x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}2x=0\\x^2+2x+5=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\\left(x^2+2x+1\right)+4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\\left(x+1\right)^2+4=0\left(vô..lí\right)\end{matrix}\right.\)

\(b,ĐKXĐ:\left\{{}\begin{matrix}x\ne1\\x\ne3\\x\ne4\end{matrix}\right.\\ \dfrac{x^2-4x}{x^2-5x+4}-\dfrac{1}{2}=\dfrac{x+1}{x-3}\\ \Leftrightarrow\dfrac{x\left(x-4\right)}{\left(x-1\right)\left(x-4\right)}-\dfrac{1}{2}=\dfrac{x+1}{x-3}\\ \Leftrightarrow\dfrac{x}{x-1}-\dfrac{1}{2}-\dfrac{x+1}{x-3}=0\\ \Leftrightarrow\dfrac{2x\left(x-3\right)}{2\left(x-1\right)\left(x-3\right)}-\dfrac{\left(x-1\right)\left(x-3\right)}{2\left(x-1\right)\left(x-3\right)}-\dfrac{2\left(x+1\right)\left(x-1\right)}{2\left(x-1\right)\left(x-3\right)}=0\)

\(\Leftrightarrow\dfrac{2x^2-6x}{2\left(x-1\right)\left(x-3\right)}-\dfrac{x^2-4x+3}{2\left(x-1\right)\left(x-3\right)}-\dfrac{2x^2-2}{\left(x-1\right)\left(x-3\right)}=0\)

\(\Leftrightarrow\dfrac{2x^2-6x-x^2+4x-3-2x^2+2}{2\left(x-1\right)\left(x-3\right)}=0\)

\(\Rightarrow-x^2-2x-1=0\)

\(\Leftrightarrow x^2+2x+1=0\\ \Leftrightarrow\left(x+1\right)^2=0\\ \Leftrightarrow x+1=0\\ \Leftrightarrow x=-1\left(tm\right)\)

 

1:

a: =>(|x|+4)(|x|-1)=0

=>|x|-1=0

=>x=1; x=-1

b: =>x^2-4>=0

=>x>=2 hoặc x<=-2

d: =>|2x+5|=2x-5

=>x>=5/2 và (2x+5-2x+5)(2x+5+2x-5)=0

=>x=0(loại)

20 tháng 4 2022

a,\(x\in\left\{5;1,5;\dfrac{-4}{3}\right\}\)

9 tháng 3 2022

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

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

\(ĐK:x\ne1;-3\)

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

\(\Leftrightarrow2x\left(x+3\right)+4=\left(2x-5\right)\left(x-1\right)\)

\(\Leftrightarrow2x^2+6x+4=2x^2-2x-5x+5\)

\(\Leftrightarrow13x=1\)

\(\Leftrightarrow x=\dfrac{1}{13}\left(tm\right)\)

26 tháng 3 2022

a, \(-2x\ge-5\Leftrightarrow x\le\dfrac{5}{2}\)

b, TH1 : \(\left\{{}\begin{matrix}x-1>0\\x+3>0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>1\\x>-3\end{matrix}\right.\Leftrightarrow x>1\)

TH2 : \(\left\{{}\begin{matrix}x-1< 0\\x+3< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< 1\\x< -3\end{matrix}\right.\Leftrightarrow x< -3\)

 

14 tháng 3 2021

chỗ dấu suy ra thứ 2 e ko hiểu lắm ạ