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7 tháng 8 2021

<=> \(4x^2-12x^2+12x+9\left(x^2-2x+1\right)=0\) 

,<=> \(4x^2-12x^2+12x+9x^2-18x+9=0\)

<=> \(x^2-6x+9=0\)

<=> \(x=3\)

22 tháng 2 2020

ai giúp mình câu (a) với ạ

NV
22 tháng 2 2020

ĐKXĐ: \(x\ne\pm\frac{3}{2}\)

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

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

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

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

\(\Leftrightarrow\left[{}\begin{matrix}2x+3=2x-3\left(vn\right)\\2x+3=4\left(2x-3\right)\Rightarrow x=\frac{5}{2}\end{matrix}\right.\)

6 tháng 8 2019

a) \(x^2-12x+11\)\(=0\)

\(\Leftrightarrow\left(x-6\right)^2-25=0\)

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

\(\Leftrightarrow\left(x-1\right)\left(x-11\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x-11=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=11\end{matrix}\right.\)

6 tháng 8 2019

a)\(x^2-12x+11=0\)

\(x^2-x-11x+11=0\)

\(\left(x^2-x\right)-\left(11x-11\right)=0\)

\(x\left(x-1\right)-11\left(x-1\right)=0\)

\(\left(x-1\right)\left(x-11\right)=0\)

\(=>\left[{}\begin{matrix}x-1=0\\x-11=0\end{matrix}\right.\)

\(=>\left[{}\begin{matrix}x=1\\x=11\end{matrix}\right.\)

b)\(4x^2-4x-3=0\)

\(4x^2-2x+6x-3=0\)

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

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

\(=>\left[{}\begin{matrix}2x-1=0\\2x+3=0\end{matrix}\right.\)

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

c)\(4x^2-12x-7=0\)

\(4x^2-14x+2x-7=0\)

\(2x\left(2x-7\right)+\left(2x-7\right)=0\)

\(\left(2x-7\right)\left(2x+1\right)=0\)

\(=>\left[{}\begin{matrix}2x-7=0\\2x+1=0\end{matrix}\right.\)

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

23 tháng 7 2021

a) \(x^2-\frac{1}{49}=0\)

<=> \(\left(x-\frac{1}{7}\right)\left(x+\frac{1}{7}\right)=0\)

<=> \(\orbr{\begin{cases}x-\frac{1}{7}=0\\x+\frac{1}{7}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{7}\\x=-\frac{1}{7}\end{cases}}\)

Vậy x = \(\pm\frac{1}{7}\)

b) \(64-\frac{1}{4}x^2=0\)

<=> \(\left(8-\frac{1}{2}x\right)\left(8+\frac{1}{2}x\right)=0\)

<=> \(\orbr{\begin{cases}8-\frac{1}{2}x=0\\8+\frac{1}{2}x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=16\\x=-16\end{cases}}\)

Vậy \(x=\pm16\)

c) 9x2 + 12x + 4 = 0

<=> (3x + 2)2 = 0

<=> 3x + 2 = 0 

<=> x = -2/3

Vậy x = -2/3

e) \(x^2+\frac{1}{4}=x\) 

<=> \(x^2-x+\frac{1}{4}=0\)

<=> \(\left(x-\frac{1}{2}\right)^2=0\)

<=> \(x=\frac{1}{2}\)

Vậy \(x=\frac{1}{2}\)

23 tháng 7 2021

d, sửa đề : \(x^2+4=4x\Leftrightarrow x^2-4x+4=0\Leftrightarrow\left(x-2\right)^2=0\Leftrightarrow x=2\)

i, \(4-\frac{12}{x}+\frac{9}{x^2}=0\)ĐK : \(x\ne0\)

Vì \(x\ne0\)Nhân 2 vế với \(x^2\)phương trình có dạng 

\(4x^2-12x+9=0\Leftrightarrow\left(2x-3\right)^2=0\Leftrightarrow x=\frac{3}{2}\)

10 tháng 12 2021

Câu 9:

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

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

10 tháng 12 2021

\(9,\Leftrightarrow x^2\left(x-2\right)-\left(x-2\right)=0\\ \Leftrightarrow\left(x-2\right)\left(x-1\right)\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=-1\\x=2\end{matrix}\right.\\ 11,\Leftrightarrow x^2+5x-x-5=0\\ \Leftrightarrow\left(x+5\right)\left(x-1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=-5\end{matrix}\right.\\ 12,\Leftrightarrow\left(x+1\right)^2-36=0\\ \Leftrightarrow\left(x+7\right)\left(x-5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-7\\x=5\end{matrix}\right.\\ 13,\Leftrightarrow x^3-25x-x^3-8=17\\ \Leftrightarrow-25x=25\Leftrightarrow x=-1\\ 14,\Leftrightarrow x\left(2x^2+8x-3x-12\right)=0\\ \Leftrightarrow x\left(x+4\right)\left(2x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=-4\\x=\dfrac{3}{2}\end{matrix}\right.\)

11 tháng 10 2020

a) \(x\left(x-2\right)-7x+14=0\)

\(\Leftrightarrow x\left(x-2\right)-7\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(x-7\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=7\end{cases}}\)

b) \(x^2\left(x-3\right)+12-4x=0\)

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

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

\(\Leftrightarrow\orbr{\begin{cases}x=3\\x^2=4\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=\pm2\end{cases}}\)

c) \(x^2+12x-13=0\)

\(\Leftrightarrow\left(x^2-x\right)+\left(13x-13\right)=0\)

\(\Leftrightarrow x\left(x-1\right)+13\left(x-1\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+13\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=1\\x=-13\end{cases}}\)

d) \(4x^2-4x=8\)

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

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

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

e) \(x^2-6x=1\)

\(\Leftrightarrow\left(x-3\right)^2=10\)

\(\Leftrightarrow\orbr{\begin{cases}x-3=\sqrt{10}\\x-3=-\sqrt{10}\end{cases}}\Rightarrow\orbr{\begin{cases}x=3+\sqrt{10}\\x=3-\sqrt{10}\end{cases}}\)

11 tháng 10 2020

a) x( x - 2 ) - 7x + 14 = 0

<=> x( x - 2 ) - 7( x - 2 ) = 0

<=> ( x - 2 )( x - 7 ) = 0

<=> \(\orbr{\begin{cases}x-2=0\\x-7=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=7\end{cases}}\)

b) x2( x - 3 ) + 12 - 4x = 0

<=> x2( x - 3 ) - 4( x - 3 ) = 0

<=> ( x - 3 )( x2 - 4 ) = 0

<=> \(\orbr{\begin{cases}x-3=0\\x^2-4=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=\pm2\end{cases}}\)

c) x2 + 12x - 13 = 0

<=> x2 - x + 13x - 13 = 0

<=> x( x - 1 ) + 13( x - 1 ) = 0

<=> ( x - 1 )( x + 13 ) = 0

<=> \(\orbr{\begin{cases}x-1=0\\x+13=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=1\\x=-13\end{cases}}\)

d) 4x2 - 4x = 8

<=> 4( x2 - x ) = 8

<=> x2 - x = 2

<=> x2 - x - 2 = 0

<=> x2 + x - 2x - 2 = 0

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

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

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

e) x2 - 6x = 1

<=> x2 - 6x + 9 = 1 + 9

<=> ( x - 3 )2 = 10

<=> ( x - 3 )2 = ( ±√10 )2

<=> \(\orbr{\begin{cases}x-3=\sqrt{10}\\x-3=-\sqrt{10}\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=3+\sqrt{10}\\x=3-\sqrt{10}\end{cases}}\)

23 tháng 9 2018

1,=\(x^2-3x-2x^2+6x=-x^2+3x\)

2,=\(3x^2-x-5+15x=3x^2+14x-5\)

3,=\(5x+15-6x^2-6x=-6x^2-x+15\)

4,=\(4x^2+12x-x-3=4x^2+11x-3\)

5: =>(x+5)^3=0

=>x+5=0

=>x=-5

6: =>(2x-3)^2=0

=>2x-3=0

=>x=3/2

7: =>(x-6)(x-10)=0

=>x=10 hoặc x=6

8: \(\Leftrightarrow x^3-12x^2+48x-64=0\)

=>(x-4)^3=0

=>x-4=0

=>x=4

24 tháng 12 2021

b: 

1: \(\Leftrightarrow2x\left(x+2\right)=0\)

=>x=0 hoặc x=-2