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15 tháng 8 2019

a, x=2.5:7=10/7

b, 3x+1/3=4x-1

3x+1/3-4x+1=0

-x+4/3=0

-x=-4/3

x=4/3

15 tháng 8 2019

c, 2-6x=5x+2

2-6x-5x-2=0

-11x=0

x=0

d, ????????

22 tháng 10 2019

1. \(6x^3-8=40\\ 6x^3=48\\ x^3=8\\ \Rightarrow x=2\)Vậy x = 2

2. \(4x^5+15=47\\ 4x^5=32\\ x^5=8\\ \Rightarrow x\in\varnothing\left(\text{vì }x\in N\right)\)Vậy x ∈ ∅

3. \(2x^3-4=12\\ 2x^3=16\\ x^3=8\\ \Rightarrow x=2\)Vậy x = 2

4. \(5x^3-5=0\\ 5x^3=5\\ x^3=1\\ \Rightarrow x=1\)Vậy x = 1

5. \(\left(x-5\right)^{2016}=\left(x-5\right)^{2018}\\ \Rightarrow\left[{}\begin{matrix}x-5=0\\x-5=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5\\x=6\end{matrix}\right.\)Vậy \(x\in\left\{5;6\right\}\)

6. \(\left(3x-2\right)^{20}=\left(3x-1\right)^{20}\\ \Rightarrow3x-2=3x-1\\ 3x-3x=2-1\\ 0=1\left(\text{vô lí}\right)\)Vậy x ∈ ∅

7. \(\left(3x-1\right)^{10}=\left(3x-1\right)^{20}\\ \left(3x-1\right)^{10}=\left[\left(3x-1\right)^2\right]^{10}\\ \Rightarrow\left(3x-1\right)^2=3x-1\\ \left(3x-1\right)^2-\left(3x-1\right)=0\\ \left(3x-1\right)\left[\left(3x-1\right)-1\right]=0\\ \left(3x-1\right)\left(3x-2\right)=0\\ \Rightarrow\left[{}\begin{matrix}3x-1=0\\3x-2=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}3x=1\\3x=2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{1}{3}\left(\text{loại vì }x\in N\right)\\x=\frac{2}{3}\left(\text{loại vì }x\in N\right)\end{matrix}\right.\)Vậy x ∈ ∅

8. \(\left(2x-1\right)^{50}=2x-1\\ \left(2x-1\right)^{50}-\left(2x-1\right)=0\\ \left(2x-1\right)\left[\left(2x-1\right)^{49}-1\right]=0\\ \Rightarrow\left[{}\begin{matrix}2x-1=0\\\left(2x-1\right)^{49}=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=1\\2x-1=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\frac{1}{2}\left(\text{loại vì }x\in N\right)\\x=1\left(t/m\right)\end{matrix}\right.\)Vậy x = 1

9. \(\left(\frac{x}{3}-5\right)^{2000}=\left(\frac{x}{3}-5\right)^{2008}\\ \left(\frac{x}{3}-5\right)^{2008}-\left(\frac{x}{3}-5\right)^{2000}=0\\ \left(\frac{x}{3}-5\right)^{2000}\left[\left(\frac{x}{3}-5\right)^8-1\right]=0\\ \Rightarrow\left[{}\begin{matrix}\left(\frac{x}{3}-5\right)^{2000}=0\\\left(\frac{x}{3}-5\right)^8=1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}\frac{x}{3}-5=0\\\frac{x}{3}-5=1\\\frac{x}{3}-5=-1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}\frac{x}{3}=5\\\frac{x}{3}=6\\\frac{x}{3}=4\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=5\cdot3=15\\x=6\cdot3=18\\x=4\cdot3=12\end{matrix}\right.\)Vậy \(x\in\left\{15;18;12\right\}\)

22 tháng 10 2019

\(1.6x^3-8=40\\ \Leftrightarrow6x^3=48\\ \Leftrightarrow x^3=8\Leftrightarrow x^3=2^3=\left(-2\right)^3\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)

Vậy \(x\in\left\{2;-2\right\}\)

\(2.4x^3+15=47\) (T nghĩ đề là mũ 3)

\(\Leftrightarrow4x^3=32\Leftrightarrow x^3=8=2^3=\left(-2\right)^3\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)

Vậy \(x\in\left\{2;-2\right\}\)

Câu 3, 4 tương tự nhé.

28 tháng 10 2021
Jdjsjsnnsndndndndndnnejejekekeodkndnfndndnnfnfnfnfnndkakwowoeijrhfbd historical đó có bột all of có lúc có là do sốc xó óc đó Úc được xây ff xóc đi h Hà đó ơi clan. Gì ơi có óc cm mà đi mà số of con là clair đó Úc áo
18 tháng 1 2019

1)6x-8=3x+1

6x-3x=1+8

3x=9

x=3

Vậy x=3

2: 12-10x=25-30x

=>20x=13

=>x=13/20

3: \(3\left(2x+3\right)-2\left(4x-5\right)=10x+21\)

=>6x+9-8x+10=10x+21

=>10x+21=-2x+19

=>12x=-2

=>x=-1/6

4: \(\Leftrightarrow25x-15-6x+12=11-5x\)

=>19x-3=11-5x

=>24x=14

=>x=7/12

5: \(\Leftrightarrow8-12x-5+10x=4-6x\)

=>4-6x=-2x+3

=>-4x=-1

=>x=1/4

6: \(\Leftrightarrow32x-24-6+9x=13-40x\)

=>41x-30=13-40x

=>81x=43

=>x=43/81

7: \(\Leftrightarrow10x-5+20x=5x-11\)

=>30x-5=5x-11

=>25x=-6

=>x=-6/25

6 tháng 8 2018

\(1\frac{1}{2}+x=\frac{3}{2}-7\)

<=> \(\frac{3}{2}+x=\frac{-11}{2}\)

<=> \(x=-7\)

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

<=> \(\frac{1}{3}:3x=\frac{-21}{4}\)

<=> \(3x=\frac{-4}{63}\)

<=> \(x=\frac{4}{189}\)

\(\frac{4}{5}.x=\frac{8}{35}\)

<=> \(x=\frac{2}{7}\)

\(\frac{2}{3x}-\frac{1}{4}=\frac{7}{1}\)

<=> \(\frac{2}{3x}=\frac{29}{4}\)

=> \(8=87x\)

<=> \(x=\frac{8}{87}\)

\(\frac{3}{5x}+\frac{1}{2}=\frac{1}{7}\)

<=> \(\frac{3}{5x}=\frac{-5}{14}\)

<=> \(-25x=42\)

<=> \(x=\frac{-42}{25}\)

\(1-\left(5\frac{3}{8}+x-7\frac{5}{24}\right):\left(-16.\frac{2}{3}\right)=0\)

<=> \(1-\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{-32}{3}=0\)

<=> \(\frac{43}{8}+x-\frac{173}{24}=\frac{-32}{3}\)

<=> \(\frac{43}{8}+x=\frac{-83}{24}\)

<=> \(x=\frac{-53}{6}\)

học tốt

15 tháng 11 2017

a) \(\left(x+2\right)^2-\left(3x-7\right)^2=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=3x-7\\x+2=-3x+7\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3x=-2-7\\x+3x=-2+7\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}-2x=-9\\4x=5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=\dfrac{5}{4}\end{matrix}\right.\)

Mấy câu kia tương tự.

15 tháng 11 2017

a) \(\left(x+2\right)^2-\left(3x-7\right)^2=0\)

\(\Leftrightarrow\left(x+2-3x+7\right)\left(x+2+3x-7\right)=0\)

\(\Leftrightarrow\left(-2x+9\right)\left(4x-5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}-2x+9=0\\4x-5=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}-2x=-9\\4x=5\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-9}{-2}=\dfrac{9}{2}\\x=\dfrac{5}{4}\end{matrix}\right.\)

Vậy \(x=\dfrac{9}{2}\) hoặc \(x=\dfrac{5}{4}\)

b) lộn đề à

c) \(25\left(x-3\right)^2-49\left(2x+1\right)^2=0\)

\(\Leftrightarrow5^2\left(x-3\right)^2-7^2\left(2x+1\right)^2=0\)

\(\Leftrightarrow\left[5\left(x-3\right)\right]^2-\left[7\left(2x+1\right)\right]^2=0\)

\(\Leftrightarrow\left(5x-15\right)^2-\left(14x+7\right)^2=0\)

\(\Leftrightarrow\left(5x-15-14x-7\right)\left(5x-15+14x+7\right)=0\)

\(\Leftrightarrow\left(-9x-22\right)\left(19x-8\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}-9x-22=0\\19x-8=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}-9x=22\\19x=8\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{22}{-9}=\dfrac{-22}{9}\\x=\dfrac{8}{19}\end{matrix}\right.\)

Vậy \(x=\dfrac{-22}{9}\) hoặc \(x=\dfrac{8}{19}\)

d) \(9\left(3x-2\right)^2=121\left(1-4x\right)^2\)

\(\Leftrightarrow9\left(3x-2\right)^2-121\left(1-4x\right)^2=0\)

\(\Leftrightarrow3^2\left(3x-2\right)^2-11^2\left(1-4x\right)^2=0\)

\(\Leftrightarrow\left[3\left(3x-2\right)\right]^2-\left[11\left(1-4x\right)\right]^2=0\)

\(\Leftrightarrow\left(9x-6\right)^2-\left(11-44x\right)^2=0\)

\(\Leftrightarrow\left(9x-6-11+44x\right)\left(9x-6+11-44x\right)=0\)

\(\Leftrightarrow\left(53x-17\right)\left(-35x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}53x-17=0\\-35x+5=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}53x=17\\-35x=-5\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{17}{53}\\x=\dfrac{-5}{-35}=\dfrac{1}{7}\end{matrix}\right.\)

Vậy \(x=\dfrac{17}{53}\) hoặc \(x=\dfrac{1}{7}\)

19 tháng 1 2019

a) 2x + 5 = x - 7

    2x -x   = -7 - 5

    x         = -12

19 tháng 1 2019

b) | x | = | 8 |

    | x | = 8

=> x = 8

   hoặc x = -8

28 tháng 8 2020

a) \(\left|2x+1\right|=\left|1-x\right|\)

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

b) \(\left|5x-4\right|=\left|x+2\right|\)

\(\Leftrightarrow\orbr{\begin{cases}5x-4=x+2\\5x-4=-x-2\end{cases}}\Leftrightarrow\orbr{\begin{cases}4x=6\\6x=2\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{1}{3}\end{cases}}\)

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

\(\Leftrightarrow\orbr{\begin{cases}2x-3=3x+2\\2x-3=-3x-2\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-5\\5x=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=-5\\x=\frac{1}{5}\end{cases}}\)

d) \(\left|2+3\right|=\left|4x-3\right|\Leftrightarrow\left|4x-3\right|=5\)

\(\Rightarrow\orbr{\begin{cases}4x-3=5\\4x-3=-5\end{cases}}\Leftrightarrow\orbr{\begin{cases}4x=8\\4x=-2\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=-\frac{1}{2}\end{cases}}\)

e) \(\left|\frac{5}{4}-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\Leftrightarrow\left|\frac{5}{8}x+\frac{3}{5}\right|=\frac{9}{4}\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{5}{8}x+\frac{3}{5}=\frac{9}{4}\\\frac{5}{8}x+\frac{3}{5}=-\frac{9}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}\frac{5}{8}x=\frac{33}{20}\\\frac{5}{8}x=-\frac{57}{20}\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{66}{25}\\x=-\frac{114}{25}\end{cases}}\)

28 tháng 8 2020

\(\left|2x+1\right|=\left|1-x\right|\)

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

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

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

b. \(\left|5x-4\right|=\left|x+2\right|\)

\(\Leftrightarrow\orbr{\begin{cases}5x-4=x+2\\5x-4=-x-2\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}5x-x=4+2\\5x+x=4-2\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}4x=6\\6x=2\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{1}{3}\end{cases}}\)

c. \(\left|2x-3\right|-\left|3x+2\right|=0\)

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

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

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

\(\Leftrightarrow\orbr{\begin{cases}-x=5\\5x=1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-5\\x=\frac{1}{5}\end{cases}}\)

d, e tương tự

10 tháng 5 2016

câu1

(3x-1).(1/2x5)=0

=>3x-1=0               hoặc  1/2x5=0

=>x=1/3                            =>x=0

câu2

1/4+1/3 :(2x-1)=5

=> 1/3:(2x-1)=19/4

=>2x-1       =57/4

=>2x=61/4

=>x=61/8

còn hai câu sau bn ghi đề mik ko hỉu

10 tháng 5 2016

1.

a)(3x-1)(1/2x5)=0

=>3x-1=0 hoặc 1/2x5=0

3x=0+1               x=0:1/2:5

x=1/3                  x=0

Vậy x=1/3 hoặc x=0

b)1/4+1/3:(2x-1)=5

1/3:(2x-1)=5-1/4=20/4-1/4=19/4

2x-1=1/3:19/4=1/3*4/19=4/57

2x=4/57+1=4/57+57/57=61/57

x=61/57:2=61/57*1/2=61/114

Vậy x=61/114

c)(2x+2/5)2-9/25=0=02-9/25

=>2x+2/5=0

2x=0-2/5

x=-2/5:2=-2/5*1/2

x=-1/5

Vậy x=-1/5

d)(3x-1/2)3+1/9=0=03+1/9

=>3x-1/2=0

3x=0+1/2

x=1/2:3=1/2*1/3

x=1/6

Vậy x=1/6