\(\in\) Q, biết

a) (x-\(\dfrac{1}{3}\))

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25 tháng 7 2017

a, \(\left(x-\dfrac{1}{3}\right)^2=0\)

=> \(x-\dfrac{1}{3}=0\)

=>\(x=\dfrac{1}{3}\)

Vậy \(x=\dfrac{1}{3}\)

b, \(\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\)

=>\(\left(x+\dfrac{1}{2}\right)^2=\left(\dfrac{1}{8}\right)^2\)

=> \(x+\dfrac{1}{2}=\dfrac{1}{8}\)

=> \(x=-\dfrac{3}{8}\)

c, (2x - 1)^3 = 8

=> (2x - 1)^3 = 2^3

=> 2x - 1 = 2

=> 2x = 3

=> x = 3/2

25 tháng 7 2017

a) (x - \(\dfrac{1}{3}\))2=0

=> x- \(\dfrac{1}{3}\)=0

x=\(\dfrac{1}{3}\)

b) (x + \(\dfrac{1}{2}\))2=\(\dfrac{1}{16}\)

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

TH1: x+ \(\dfrac{1}{2}\)=\(\dfrac{1}{4}\)

x= \(\dfrac{-1}{4}\)

TH2 : x + \(\dfrac{1}{2}\)= \(\dfrac{-1}{4}\)

x = \(\dfrac{-3}{4}\)

Vậy x = \(\dfrac{-1}{4}\); \(\dfrac{-3}{4}\)

c) (2x-1)3 =8

=> 2x - 1 = 2

2x = 3

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

a: \(\left|x\right|=3+\dfrac{1}{5}=\dfrac{16}{5}\)

mà x<0

nên x=-16/5

b: \(\left|x\right|=-2.1\)

nên \(x\in\varnothing\)

c: \(\left|x-3.5\right|=5\)

=>x-3,5=5 hoặc x-3,5=-5

=>x=8,5 hoặc x=-1,5

d: \(\left|x+\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)

=>|x+3/4|=1/2

=>x+3/4=1/2 hoặc x+3/4=-1/2

=>x=-1/4 hoặc x=-5/4

19 tháng 11 2022

a: =>1/6x=-49/60

=>x=-49/60:1/6=-49/60*6=-49/10

b: =>3/2x-1/5=3/2 hoặc 3/2x-1/5=-3/2

=>x=17/15 hoặc x=-13/15

c: =>1,25-4/5x=-5

=>4/5x=1,25+5=6,25

=>x=125/16

d: =>2^x*17=544

=>2^x=32

=>x=5

i: =>1/3x-4=4/5 hoặc 1/3x-4=-4/5

=>1/3x=4,8 hoặc 1/3x=-0,8+4=3,2

=>x=14,4 hoặc x=9,6

j: =>(2x-1)(2x+1)=0

=>x=1/2 hoặc x=-1/2

10 tháng 6 2017

a) \(\left(x-\dfrac{1}{2}\right)^2=0\Rightarrow x-\dfrac{1}{2}=0\Rightarrow x=\dfrac{1}{2}\)

b) Vì \(\left(x-2\right)^2=1\Rightarrow\left\{{}\begin{matrix}x-2=2\\x-2=-2\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=4\\x=0\end{matrix}\right.\)

Vậy x = 4 hoặc x = 0

c) Vì \(\left(2.x-1\right)^3=-8\Rightarrow2.x-1=-2\Rightarrow2.x=-1\Rightarrow x=-\dfrac{1}{2}\)

d) Vì \(\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\Rightarrow\left\{{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{1}{4}\\x+\dfrac{1}{2}=-\dfrac{1}{4}\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{1}{4}\\x=-\dfrac{3}{4}\end{matrix}\right.\)

23 tháng 6 2017

a) \(\left(x-\dfrac{1}{2}\right)^2=0\Leftrightarrow x-\dfrac{1}{2}=0\Leftrightarrow x=\dfrac{1}{2}\)

b) \(\left(x-2\right)^2=1\Leftrightarrow\left\{{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

c) \(\left(2x-1\right)^3=-8\Leftrightarrow2x-1=-2\Leftrightarrow2x=-1\Leftrightarrow x=\dfrac{-1}{2}\) d) \(\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\Leftrightarrow x+\dfrac{1}{2}=\dfrac{1}{4}\Leftrightarrow x=\dfrac{-1}{4}\)

20 tháng 8 2017

a) \(\left(x-\dfrac{1}{2}\right)^2=0\Leftrightarrow x-\dfrac{1}{2}=0\Leftrightarrow x=\dfrac{1}{2}\) vậy \(x=\dfrac{1}{2}\)

b) \(\left(x-2\right)^2=1\Leftrightarrow\left[{}\begin{matrix}x-2=\sqrt{1}\\x-2=-\sqrt{1}\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

vậy \(x=3;x=1\)

c) \(\left(2x-1\right)^3=-8\Leftrightarrow2x-1=\sqrt[3]{-8}=-2\Leftrightarrow2x=-1\)

\(\Leftrightarrow x=\dfrac{-1}{2}\) \(\) vậy \(x=\dfrac{-1}{2}\)

d) \(\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=\sqrt{\dfrac{1}{16}}\\x+\dfrac{1}{2}=-\sqrt{\dfrac{1}{16}}\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=\dfrac{1}{4}\\x+\dfrac{1}{2}=-\dfrac{1}{4}\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-1}{4}\\x=\dfrac{-3}{4}\end{matrix}\right.\) vậy \(x=\dfrac{-1}{4};x=\dfrac{-3}{4}\)

24 tháng 8 2018

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

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

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

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

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

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

\(\dfrac{4}{3}x=-\dfrac{13}{3}\)

\(x=-\dfrac{13}{3}:\dfrac{4}{3}\)

\(x=-\dfrac{13}{4}\)

Vậy...............

\(b,\left(x+\dfrac{1}{2}\right)\left(\dfrac{3}{4}-x\right)=0\)

\(\Rightarrow\left\{{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{3}{4}-x=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{3}{4}\end{matrix}\right.\)

Vậy................

\(c,\dfrac{2x-1}{-3+2}=0\)

\(\Rightarrow2x-1=0\)

\(\Rightarrow x=\dfrac{1}{2}\)

Vậy.............

27 tháng 11 2022

b: =>(3x-1)(3x+1)(2x+3)=0

hay \(x\in\left\{\dfrac{1}{3};-\dfrac{1}{3};-\dfrac{3}{2}\right\}\)

c: \(\Leftrightarrow\left|2x-\dfrac{1}{3}\right|=\dfrac{5}{6}+\dfrac{3}{4}=\dfrac{19}{12}\)

=>2x-1/3=19/12 hoặc 2x-1/3=-19/12

=>2x=23/12 hoặc 2x=-15/12=-5/4

=>x=23/24 hoặc x=-5/8

d: \(\Leftrightarrow-\dfrac{5}{6}\cdot x+\dfrac{3}{4}=-\dfrac{3}{4}\)

=>-5/6x=-3/2

=>x=3/2:5/6=3/2*6/5=18/10=9/5

e: =>2/5x-1/2=3/4 hoặc 2/5x-1/2=-3/4

=>2/5x=5/4 hoặc 2/5x=-1/4

=>x=5/4:2/5=25/8 hoặc x=-1/4:2/5=-1/4*5/2=-5/8

f: =>14x-21=9x+6

=>5x=27

=>x=27/5

h: =>(2/3)^2x+1=(2/3)^27

=>2x+1=27

=>x=13

i: =>5^3x*(2+5^2)=3375

=>5^3x=125

=>3x=3

=>x=1

a) \(7-\sqrt{x}=0\)

\(\Rightarrow\sqrt{x}=7\)

\(\Rightarrow x=\left(\sqrt{7}\right)^2\)

b) \(5\sqrt{x}+1=40\)

\(\Rightarrow5\sqrt{x}=39\)

\(\Rightarrow\sqrt{x}=7,8\)

\(\Rightarrow x=\left(\sqrt{7,8}\right)^2\)

c) \(\dfrac{5}{12}\sqrt{x}-\dfrac{1}{6}=\dfrac{1}{3}\)

\(\Rightarrow\dfrac{5}{12}\sqrt{x}=\dfrac{1}{2}\)

\(\Rightarrow\sqrt{x}=1,2\)

\(\Rightarrow x=\left(\sqrt{1,2}\right)^2\)

d) \(4x^2-1=0\)

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

\(\Rightarrow\left[{}\begin{matrix}2x-1=0\Rightarrow x=0,5\\2x+1=0\Rightarrow x=-0,5\end{matrix}\right.\)

e) \(\sqrt{x+1}-2=0\)

\(\Rightarrow\sqrt{x+1}=2\)

\(\Rightarrow x+1=1,414\)

\(\Rightarrow x=0,414\)

f) \(2x^2+0,82=1\)

\(\Rightarrow2x^2=0,18\)

\(\Rightarrow x^2=0,09\)

\(\Rightarrow x=\pm0,3\)

g) Không có kết quả

11 tháng 9 2019

Tính chất của dãy tỉ số bằng nhau

b: 2x^3-1=15

=>2x^3=16

=>x=2

\(\dfrac{x+16}{9}=\dfrac{y-25}{16}=\dfrac{z+9}{25}\)

=>\(\dfrac{y-25}{16}=\dfrac{z+9}{25}=\dfrac{18}{9}=2\)

=>y-25=32; z+9=50

=>y=57; z=41

d: 3/5x=2/3y

=>9x=10y

=>x/10=y/9=k

=>x=10k; y=9k

x^2-y^2=38

=>100k^2-81k^2=38

=>19k^2=38

=>k^2=2

TH1: k=căn 2

=>\(x=10\sqrt{2};y=9\sqrt{2}\)

TH2: k=-căn 2

=>\(x=-10\sqrt{2};y=-9\sqrt{2}\)

a: =>13/6x=-1/2

=>x=-1/2:13/6=-1/2x6/13=-6/26=-3/13

b: =>2x-1=1/2 hoặc 2x-1=-1/2

=>2x=3/2 hoặc 2x=1/2

=>x=3/4 hoặc x=1/4

c: =>(x-4)(x+4)(4-5x)=0

hay \(x\in\left\{4;-4;\dfrac{4}{5}\right\}\)