K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

28 tháng 11 2019

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

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

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

\(\Rightarrow\orbr{\begin{cases}x=\frac{11}{3}\\x=-\frac{7}{3}\end{cases}}\)

28 tháng 11 2019

\(\left(\frac{x-2}{3}\right)^2-1=8\)

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

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

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

              

28 tháng 8 2021

a,

\(5^{x+4}-3.5^{x+3}=2.5^{11}\)

\(\Rightarrow5^{x+3}\left(5-3\right)=2.5^{11}\)

\(\Rightarrow5^{x+3}2=2.5^{11}\)

\(\Rightarrow5^{x+3}=5^{11}\)

\(\Rightarrow x+3=11\)

\(\Rightarrow x=8\)

28 tháng 8 2021

b, (Check lai xem de sai o dau khong nhe)

\(3.5^{x+2}+4.5^{x+3}=19.5^{10}\)

Dat 5x ra ben ngoai

\(\Rightarrow5^x.5^23+5^x:5^{-3}.4\)

\(\Rightarrow5^x\left(5^2.3+5^{-3}.4\right)\)

\(\Rightarrow5^x\left(5^{-3}.5^5.3+5^{-3}.4\right)\)

\(\Rightarrow5^x[5^{-3}\left(5^53+4\right)\)

\(\Rightarrow5^x[5^{-3}\left(3125.3+4\right)\)

\(\Rightarrow5^x\left(5^{-3}\right).9379\)

=> Khong tim duoc gia tri cua x \(\Rightarrow x\in\varnothing\)

a) \(6.8^{x-1}+8^{x+1}=6.8^{19}+8^{21}\)

\(\Rightarrow x-1+x+1=19+21\)

\(=2x=40\)

\(\Rightarrow x=20\)

b) \(4.3^{x-1}+2.3^{x+2}=4.3^6+2.3^9\)

\(\Rightarrow x-1+x+2=6+9\)

\(\Rightarrow2x+1=15\)

\(\Rightarrow2x=14\)

\(\Rightarrow x=7\)

9 tháng 10 2016

dùng fx gõ cho hẳn hoi

12 tháng 9 2017

1)

Ta có: \(\left(x-\frac{1}{2}\right)^3=8\Rightarrow\left(x-\frac{1}{2}\right)^3=2^3\)

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

12 tháng 9 2017

\(\left(x-1\right)^3=\frac{8}{27}\Rightarrow\left(x-1\right)^3=\left(\frac{2}{3}\right)^3\)

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

5 tháng 7 2021

a) \(\left|4-x\right|+2x=3\)

<=> \(\left|4-x\right|=3-2x\)

<=> \(\orbr{\begin{cases}4-x=3-2x\left(x\le4\right)\\x-4=3-2x\left(x>4\right)\end{cases}}\)

<=> \(\orbr{\begin{cases}x=-1\left(tm\right)\\3x=7\end{cases}}\)

<=> \(\orbr{\begin{cases}x=-1\\x=\frac{7}{3}\left(ktm\right)\end{cases}}\)

Vậy x = -1

b) \(\left|x-7\right|+2x+5=6\)

<=> \(\left|x-7\right|=1-2x\)

<=> \(\orbr{\begin{cases}x-7=1-2x\left(đk:x\ge7\right)\\x-7=2x-1\left(đk:x< 7\right)\end{cases}}\)

<=> \(\orbr{\begin{cases}3x=8\\x=-6\left(tm\right)\end{cases}}\)

<=> \(\orbr{\begin{cases}x=\frac{8}{3}\left(ktm\right)\\x=-6\left(tm\right)\end{cases}}\)

Vậy x = -6

c) \(3x-\left|2x+1\right|=2\)

<=> \(\left|2x+1\right|=3x-2\)

<=> \(\orbr{\begin{cases}2x+1=3x-2\left(đk:x\ge-\frac{1}{2}\right)\\2x+1=2-3x\left(đk:x< -\frac{1}{2}\right)\end{cases}}\)

<=> \(\orbr{\begin{cases}x=3\left(tm\right)\\5x=1\end{cases}}\)

<=> \(\orbr{\begin{cases}x=3\\x=\frac{1}{5}\left(ktm\right)\end{cases}}\)

Vậy x = 3

d) \(\left|x+2\right|-x=2\)

<=> \(\left|x+2\right|=x+2\)

<=> \(\orbr{\begin{cases}x+2=x+2\left(đk:x\ge-2\right)\\x+2=-x-2\left(x< -2\right)\end{cases}}\)

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

<=> 0x = 0 (luôn đúng) và x = -2 (ktm)

Vậy x \(\ge\)-2

5 tháng 7 2021

e) \(\left|x-3\right|=21\)

<=> \(\orbr{\begin{cases}x-3=21\\3-x=21\end{cases}}\)

<=> \(\orbr{\begin{cases}x=24\\x=-18\end{cases}}\)

Vậy x = 24 hoặc x = -18

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

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

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

<=> \(\orbr{\begin{cases}x=-6\\3x=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=-6\\x=0\end{cases}}\)

Vậy x thuộc {-6; 0}

g) Ta có: \(\left|x+\frac{1}{8}\right|\ge0\forall x\)

          \(\left|x+\frac{2}{8}\right|\ge0\forall x\)

    \(\left|x+\frac{5}{8}\right|\ge0\forall x\)

=> VT = \(\left|x+\frac{1}{8}\right|+\left|x+\frac{2}{8}\right|+\left|x+\frac{5}{8}\right|\ge0\forall x\)

=> VP \(\ge0\) => \(4x\ge0\) => \(x\ge0\)

Do đó: \(x+\frac{1}{8}+x+\frac{2}{8}+x+\frac{5}{8}=4x\)

<=> \(3x+1=4x\) <=> \(x=1\left(tm\right)\)

Vậy x = 1

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

<=> \(\left|x-2\right|-\left|2x+3\right|=x-2\)(*)

Lập bảng xét dấu: 

x                     -3/2              2

x - 2        2 - x    |        2 - x    0        x - 2

2x + 3  -2x - 3   0      2x + 3  |          2x + 3

Xét x < -3/2 => pt (*) trở thành: 2 - x + 2x + 3 = x - 2

<=> x + 5 = x - 2 <=> 0x = -7 (vô lí)

Xét -3/2 \(\le\) x < 2 => pt (*) trở thành: 2 - x - 2x - 3 = x - 2

<=> 4x = 1 <=> x = 1/4 ((tm)

Xét x \(\ge\) 2 => pt (*) trở thành x - 2 - 2x - 3 = x - 2

<=> 2x = -3 <=>  x = -3/2 (ktm)

Vậy x = 1/4

i) |2x - 3| - x = |2 - x|

<=> |2x - 3| - |2 - x| = x (*)

Lập bảng xét dấu

x                    3/2               2

2x - 3   3 - 2x   0     2x - 3   |  2x - 3

2 - x     2 - x     |       2 - x    0   x - 2

Xét x < 3/2 => pt (*) trở thành: 3 - 2x - 2 + x =  x

<=> 2x = 1 <=> x = 1//2 ((tm)
Xét \(\frac{3}{2}\le x< 2\)=> pt (*) trở thành: 2x - 3 - 2 + x = x

<=> 2x = 5 <=> x = 5/2 (ktm)

Xét x \(\ge\)2 ==> pt (*) trở thành: 2x - 3 - x + 2 = x

<=> 0x = -5 (vô lí)

Vậy x = 1/2

k) 2|x - 3| - |4x - 1| = 0

<=> 2|x - 3| = |4x - 1|

<=> \(\orbr{\begin{cases}2\left(x-3\right)=4x-1\\2\left(x-3\right)=1-4x\end{cases}}\)

<=> \(\orbr{\begin{cases}2x-6=4x-1\\2x-6=1-4x\end{cases}}\)

<=> \(\orbr{\begin{cases}2x=-5\\6x=7\end{cases}}\)

<=> \(\orbr{\begin{cases}x=-\frac{5}{2}\\x=\frac{7}{6}\end{cases}}\) Vậy ...

12 tháng 7 2019

a) \(\frac{x}{x+1}=\frac{1}{2}\)

=> 2x = x + 1

=> 2x - x = 1

=> x = 1

b) \(\frac{x}{2}=\frac{x}{3}\)

=> 3x = 2x

=> 3x - 2x = 0

=> x = 0

c) \(\frac{x+1}{2}=\frac{x+1}{2017}\)

=> \(2017\left(x+1\right)=2\left(x+1\right)\)

=> 2017x + 2017 = 2x + 2

=> 2017x - 2x = 2 - 2017

=> 2015x = -2015

=> x = -2015 : 2015

=> x = -1

i) \(\frac{3}{x}=\frac{x}{2017}\)

=> x2 = 2017.3

=> x2 = 6051

=> \(\orbr{\begin{cases}x=\sqrt{6051}\\x=-\sqrt{6051}\end{cases}}\)

còn lại tự lm

\(a,\frac{x}{x+1}=\frac{1}{2}\)

\(\Rightarrow x=\frac{1}{2}.\left(x+1\right)\)

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

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

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

\(\Rightarrow x=1\)

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

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

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

\(\Rightarrow3x=2x\)

\(\Rightarrow x=0\)

\(c,\frac{x+1}{2}=\frac{x+1}{2017}\)

\(\Rightarrow x+1=\frac{x+1}{2017}.2\)

\(\Rightarrow x+1=\frac{2x+2}{2017}\)

\(\Rightarrow2017x+2017=2x+2\)

\(\Rightarrow2017x-2x=2-2017\)

\(\Rightarrow2015x=-2015\)

\(\Rightarrow x=-1\)

\(i,\frac{3}{x}=\frac{x}{2017}\)

\(\Rightarrow x=3:\frac{x}{2017}\)

\(\Rightarrow x=\frac{6051}{x}\)

\(\Rightarrow x^2=6051\)

\(\Rightarrow x=\sqrt{6051}\)

\(o,\frac{x}{3}=\frac{x+1}{2}\)

\(\Rightarrow x=\frac{x+1}{2}.3\)

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

\(\Rightarrow2x=3x+3\)

\(\Rightarrow-x=3\)

\(\Rightarrow x=-3\)

\(m,\frac{x+1}{2}=\frac{x+2}{3}\)

\(\Rightarrow x+1=\frac{x+2}{3}.2\)

\(\Rightarrow x+1=\frac{2x+4}{3}\)

\(\Rightarrow3x+3=2x+4\)

\(\Rightarrow x=1\)

\(p,\frac{x+1}{2}=x\)

\(\Rightarrow2x=x+1\)

\(\Rightarrow x=1\)

\(m,\frac{2}{x}=\frac{x}{8}\)

\(\Rightarrow x=2:\frac{x}{8}\)

\(\Rightarrow x=\frac{16}{x}\)

\(\Rightarrow x^2=16\)

\(\Rightarrow x=4\)

\(Q,\frac{x^2}{2}=\frac{8}{x^2}\)

\(\Rightarrow x^2=\frac{8}{x^2}.2\)

\(\Rightarrow x^2=\frac{16}{x^2}\)

\(\Rightarrow x^4=16\)

\(\Rightarrow x=2\)

\(r,\frac{x^3}{2}=\frac{32}{x}\)

\(\Rightarrow x^3=\frac{32}{x}.2\)

\(\Rightarrow x^3=\frac{64}{x}\)

\(\Rightarrow x^4=64\)

\(\Rightarrow x=\sqrt[4]{64}\)

27 tháng 9 2024

Bài 1:

a; \(\dfrac{7}{8}\) + \(x\) = \(\dfrac{4}{7}\)

     \(x\) = \(\dfrac{4}{7}\) - \(\dfrac{7}{8}\)

     \(x\) = \(\dfrac{32}{56}\) - \(\dfrac{49}{56}\)

     \(x=-\) \(\dfrac{49}{56}\)

Vậy \(x=-\dfrac{49}{56}\)

b; 6 - \(x\) = - \(\dfrac{3}{4}\)

         \(x\) = 6 + \(\dfrac{3}{4}\)

         \(x\) = \(\dfrac{24}{4}+\dfrac{3}{4}\)

         \(x=\dfrac{27}{4}\)

Vậy \(x=\dfrac{27}{4}\) 

c; \(\dfrac{1}{-5}\) + \(x\) = \(\dfrac{3}{4}\)

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

              \(x=\dfrac{15}{20}\) + \(\dfrac{4}{20}\)

               \(x=\dfrac{19}{20}\)

Vậy \(x=\dfrac{19}{20}\) 

27 tháng 9 2024

      Bài 1:

d; - 6 - \(x\) = - \(\dfrac{3}{5}\)

      \(x\)   = - 6 + \(\dfrac{3}{5}\)

       \(x=-\dfrac{30}{5}\) + \(\dfrac{3}{5}\)

       \(x=-\dfrac{27}{5}\)

Vậy \(x=-\dfrac{27}{5}\)

e; - \(\dfrac{2}{6}\) + \(x\) = \(\dfrac{5}{7}\)

             \(x\) = \(\dfrac{5}{7}\) + \(\dfrac{2}{6}\)

             \(x\) = \(\dfrac{15}{21}\) + \(\dfrac{1}{3}\)

              \(x=\dfrac{15}{21}\) + \(\dfrac{7}{21}\)

               \(x=\dfrac{22}{21}\)

Vậy \(x=\dfrac{22}{21}\) 

f; - 8 - \(x\) =  - \(\dfrac{5}{3}\)

          \(x\) = \(-\dfrac{5}{3}\) + 8

         \(x\) = \(\dfrac{-5}{3}\) + \(\dfrac{24}{3}\)

         \(x\) = \(\dfrac{-19}{3}\)

Vậy \(x=-\dfrac{19}{3}\) 

 

            

 

11 tháng 7 2015

Bài 1:

    \(\left(-0,125\right)\times7,9\times80\)

\(=\left(-0,9875\right)\times80\)

\(=79.\)

    \(\left(0,125\right)\times1\times0,25\times8\times\left(-4\right)\)

\(=0,125\times0,25\times8\times\left(-4\right)\)

\(=0,03125\times8\times\left(-4\right)\)

\(=0,25\times\left(-4\right)\)

\(=\left(-1\right).\)

Bài 2:

\(x+\frac{8}{3}^2=\frac{1}{9}\)

\(x+16=\frac{1}{9}\)

           \(x=\frac{1}{9}-16.MSC=9\)

           \(x=\frac{1}{9}-\frac{144}{9}\)

           \(x=\frac{-143}{9}.\)

 

           

1 tháng 11 2016

\(\left(\frac{2}{5}\right)^6:\left(\frac{2}{5}\right)^4=\left(\frac{2}{5}\right)^2=\frac{4}{25}\)

\(\left(\frac{3}{16}\right)^2:\left(\frac{9}{8}\right)^2=\frac{1}{12}\)

\(\left(\frac{2}{7}-\frac{1}{2}\right)^2=\frac{9}{196}\)