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25 tháng 2 2022

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

\(\Leftrightarrow\left(x-2\right)\left(x-5\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-2=0\\x-5=0\end{cases}\Rightarrow x\in\left\{2;5\right\}}\)

31 tháng 8 2021

a)  (x - 3)2 - 5.(x - 2) + 5 = 0.

<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0

<=> x^2 - 11x + 24 = 0

<=> (x-3)(x-8)=0

<=> x = 3 hoặc x = 8

31 tháng 8 2021

b) (2x - 1)2 - 3.(x - 2).(x + 2) - 25 = 0.

<=> 4x^2 - 4x + 1 - 3x^2 + 12 - 25 = 0

<=> x2 - 4x - 12 = 0

<=> (x+2)(x-6) = 0

<=> x = -2 hoặc x = 6

25 tháng 7 2018

\(\left(x^2-5\right)\left(x^2+1\right)=0\)

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

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

<=> \(\hept{\begin{cases}x=\sqrt{5};x=-\sqrt{5}\\x\in\varnothing\end{cases}}\)

câu còn lại tương tự nha

28 tháng 4 2018

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

\(\Rightarrow3x-1=0\Rightarrow3x=1\Rightarrow x=\frac{1}{3}\)

\(\frac{-1}{2}x+5=0\Rightarrow\frac{-1}{2}x=-5\Rightarrow x=10\)

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

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

\(\Rightarrow3x-5x-x=\frac{1}{5}+\frac{3}{2}+3\)

\(-3x=\frac{47}{10}\)

\(x=\frac{-47}{30}\)

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

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

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

\(-7x=\frac{-1}{6}\)

\(x=\frac{1}{42}\)

d) \(3.\left(3x-\frac{1}{2}\right)^3+\frac{1}{9}=0\)

\(3.\left(3x-\frac{1}{2}\right)^3=\frac{-1}{9}\)

\(\left(3x-\frac{1}{2}\right)^3=\frac{-1}{27}\)

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

\(\Rightarrow3x-\frac{1}{2}=\frac{-1}{3}\)

\(3x=\frac{1}{6}\)

\(x=\frac{1}{18}\)

Học tốt nhé bn!
 

11 tháng 8 2021

x = \(\frac{1}{18}\)nha

19 tháng 4 2020

Giúp luôn Đức Hải Nguyễn câu e:

e, (x - 1)2 + 2(x - 1)(x + 2) + (x + 2)2 = 0

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

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

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

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

Vậy S = {\(\frac{-1}{2}\)}

Chúc bn học tốt!!

19 tháng 4 2020

a) (x - 3)(5 - 2x) = 0

<=> \(\left[{}\begin{matrix}x-3=0\\5-2x=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=3\\x=\frac{5}{2}\end{matrix}\right.\)

b) (x + 5)(x - 1) - 2x(x - 1) = 0

<=> (x - 1)(x + 5 - 2x) = 0

<=> (x - 1)(5 - x) = 0

<=> \(\left[{}\begin{matrix}x-1=0\\5-x=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=1\\x=5\end{matrix}\right.\)

c) 5(x + 3)(x - 2) - 3(x + 5)(x - 2) = 0

<=> (x - 2)[5(x + 3) - 3(x + 5)] = 0

<=> (x - 2)(5x + 3 - 3x - 15) = 0

<=> (x - 2)(2x - 12) = 0

<=> \(\left[{}\begin{matrix}x-2=0\\2x-12=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=2\\x=6\end{matrix}\right.\)

d) (x - 6)(x + 1) - 2(x + 1) = 0

<=> (x + 1)(x - 6 - 2) = 0

<=> (x + 1)(x - 8) = 0

<=> \(\left[{}\begin{matrix}x+1=0\\x-8=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=-1\\x=8\end{matrix}\right.\)

Câu e thì để mình nghĩ đã :)

#Học tốt!

a: \(\dfrac{x+5}{x-1}+\dfrac{8}{x^2-4x+3}=\dfrac{x+1}{x-3}\)

=>(x+5)(x-3)+8=x^2-1

=>x^2+2x-15+8=x^2-1

=>2x-7=-1

=>x=3(loại)

b: \(\dfrac{x-4}{x-1}-\dfrac{x^2+3}{1-x^2}+\dfrac{5}{x+1}=0\)

=>(x-4)(x+1)+x^2+3+5(x-1)=0

=>x^2-3x-4+x^2+3+5x-5=0

=>2x^2+2x-6=0

=>x^2+x-3=0

=>\(x=\dfrac{-1\pm\sqrt{13}}{2}\)

e: =>x^2-2x+1+2x+2=5x+5

=>x^2+3=5x+5

=>x^2-5x-2=0

=>\(x=\dfrac{5\pm\sqrt{33}}{2}\)

g: (x-3)(x+4)*x=0

=>x=0 hoặc x-3=0 hoặc x+4=0

=>x=0;x=3;x=-4

\(1,\)

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

\(\Leftrightarrow2x\left(x-3\right)+\left(x-3\right)=0\)

\(\Leftrightarrow\left(2x+1\right)\left(x-3\right)=0\)

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

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=3\end{cases}}\)

\(2,\)

\(3x\left(x+5\right)-6\left(x+5\right)=0\)

\(\Leftrightarrow\left(3x-6\right)\left(x+5\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\x+5=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-5\end{cases}}\)

\(3,\)

\(x^4-x^2=0\)

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

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

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)

\(4,\)

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

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

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

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)

\(5,\)

\(x\left(x+6\right)-10\left(x-6\right)=0\)

\(\Leftrightarrow x^2+6x-10x+60=0\)

\(\Leftrightarrow x^2-4x+60=0\)

\(\Leftrightarrow x^2-4x+4+56=0\)

\(\Leftrightarrow\left(x-2\right)^2=-56\)(Vô lý)

=> Phương trình vô nghiệm

30 tháng 8 2020

a) tính thường

b) \(\left(x-1\right)\left(x+2\right)< 0\)

\(\Leftrightarrow\orbr{\begin{cases}x-1>0\\x+2< 0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x>1\\x< -2\end{cases}}\Leftrightarrow1< x< -2\left(ktm\right)\)

\(\Leftrightarrow\orbr{\begin{cases}x-1< 0\\x+2>0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x< 1\\x>-2\end{cases}}\Leftrightarrow-2< x< 1\left(tm\right)\)

vậy

c)\(\left(x+\frac{3}{5}\right)\left(x+1\right)< 0\Leftrightarrow\orbr{\begin{cases}x+\frac{3}{5}< 0\\x+1>0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x< -\frac{3}{5}\\x>-1\end{cases}}\Leftrightarrow-1< x< -\frac{3}{5}\left(tm\right)\)

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

\(\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{3}>0\\x+\frac{2}{5}>0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x>\frac{1}{3}\\x>-\frac{2}{5}\end{cases}}\Leftrightarrow x>\frac{1}{3}\left(tm\right)\)

\(\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{3}< 0\\x+\frac{2}{5}< 0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x< \frac{1}{3}\\x< -\frac{2}{5}\end{cases}}\Leftrightarrow x< \frac{-2}{5}\left(tm\right)\)

vậy ...

30 tháng 8 2020

a) 5/2 - x + 4/5 = 2/3 + 4/7

<=> 33/10 - x = 26/21

<=> x = 433/210

b) ( x - 1 )( x + 2 ) < 0 ( cái " x " kia là nhân à :v )

Xét 2 trường hợp

1.\(\hept{\begin{cases}x-1>0\\x+2< 0\end{cases}}\Rightarrow\hept{\begin{cases}x>1\\x< -2\end{cases}}\)( loại )

2. \(\hept{\begin{cases}x-1< 0\\x+2>0\end{cases}}\Rightarrow\hept{\begin{cases}x< 1\\x>-2\end{cases}}\Rightarrow-2< x< 1\)

Vậy -2 < x < 1

c) ( x + 3/5 )( x + 1 ) < 0

Xét hai trường hợp :

1. \(\hept{\begin{cases}x+\frac{3}{5}< 0\\x+1>0\end{cases}}\Rightarrow\hept{\begin{cases}x< -\frac{3}{5}\\x>-1\end{cases}}\Rightarrow-1< x< -\frac{3}{5}\)

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

Vậy -1 < x < -3/5

d) ( x - 1/3 )( x + 2/5 ) > 0

Xét hai trường hợp :

1.\(\hept{\begin{cases}x-\frac{1}{3}>0\\x+\frac{2}{5}>0\end{cases}}\Rightarrow\hept{\begin{cases}x>\frac{1}{3}\\x>-\frac{2}{5}\end{cases}}\Rightarrow x>\frac{1}{3}\)

2.\(\hept{\begin{cases}x-\frac{1}{3}< 0\\x+\frac{2}{5}< 0\end{cases}}\Rightarrow\hept{\begin{cases}x< \frac{1}{3}\\x< -\frac{2}{5}\end{cases}\Rightarrow}x< -\frac{2}{5}\)

Vây \(\orbr{\begin{cases}x>\frac{1}{3}\\x< -\frac{2}{5}\end{cases}}\)

30 tháng 11 2016

\(2x^2-7x+5=0\)

\(2x^2-2x-5x+5=0\)

\(2x\left(x-1\right)-5\left(x-1\right)=0\)

\(\left(x-1\right)\left(2x-5\right)=0\)

\(\left[\begin{array}{nghiempt}x-1=0\\2x-5=0\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=1\\2x=5\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=1\\x=\frac{5}{2}\end{array}\right.\)

\(x\left(2x-5\right)-4x+10=0\)

\(x\left(2x-5\right)-2\left(2x-5\right)=0\)

\(\left(2x-5\right)\left(x-2\right)=0\)

\(\left[\begin{array}{nghiempt}x-2=0\\2x-5=0\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=2\\2x=5\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=2\\x=\frac{5}{2}\end{array}\right.\)

\(\left(x-5\right)\left(x+5\right)-x\left(x-2\right)=15\)

\(x^2-25-x^2+2x=15\)

\(2x=15+25\)

\(2x=40\)

\(x=\frac{40}{2}\)

\(x=20\)

\(x^2\left(2x-3\right)-12+8x=0\)

\(x^2\left(2x-3\right)+4\left(2x-3\right)=0\)

\(\left(2x-3\right)\left(x^2+4\right)=0\)

\(2x-3=0\) (vì \(x^2\ge0\Rightarrow x^2+4\ge4>0\))

\(2x=3\)

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

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

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

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

\(\left[\begin{array}{nghiempt}x-1=0\\x+5=0\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=1\\x=-5\end{array}\right.\)

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

\(4x^2-12x+9-4x^2+4x=5\)

\(-8x=5-9\)

\(-8x=-4\)

\(x=\frac{4}{8}\)

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

\(x\left(5-2x\right)+2x\left(x-1\right)=13\)

\(5x-2x^2+2x^2-2x=13\)

\(3x=13\)

\(x=\frac{13}{3}\)

\(2\left(x+5\right)\left(2x-5\right)+\left(x-1\right)\left(5-2x\right)=0\)

\(\left(2x+10\right)\left(2x-5\right)-\left(x-1\right)\left(2x-5\right)=0\)

\(\left(2x-5\right)\left(2x+10-x+1\right)=0\)

\(\left(2x-5\right)\left(x+11\right)=0\)

\(\left[\begin{array}{nghiempt}2x-5=0\\x+11=0\end{array}\right.\)

\(\left[\begin{array}{nghiempt}2x=5\\x=-11\end{array}\right.\)

\(\left[\begin{array}{nghiempt}x=\frac{5}{2}\\x=-11\end{array}\right.\)

30 tháng 11 2016

Cảm ơn

 

1 tháng 3 2020

1. \(\Leftrightarrow\left(x-6\right)\left(x+7\right)+5\left(x-6\right)\left(3x-1\right)=0\)

\(\Leftrightarrow\left(x-6\right)\left[\left(x+7\right)+5\left(3x-1\right)\right]=0\)

\(\Leftrightarrow\left(x-6\right)\left(16x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-6=0\\16x+2=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-\frac{1}{8}\end{matrix}\right.\)

1 tháng 3 2020

4. \(\Leftrightarrow\left(x+5\right)^2\left(3x+2\right)^2-x^2\left(x+5\right)^2=0\)

\(\Leftrightarrow\left(x+5\right)^2\left[\left(3x+2\right)^2-x^2\right]=0\)

\(\Leftrightarrow\left(x+5\right)^2\left(2x+2\right)\left(4x+2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left(x+5\right)^2=0\\2x+2=0\\4x+2=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\2x=-2\\4x=-2\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=-1\\x=-\frac{1}{2}\end{matrix}\right.\)