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5 tháng 3 2023

\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{3}x-\dfrac{8}{15}=0\\2,5+\left(-\dfrac{7}{5}\right)\div x=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{3}x=0+\dfrac{8}{15}\\-\dfrac{7}{5}\div x=0-2,5\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{3}x=\dfrac{8}{15}\\-\dfrac{7}{5}\div x=-2,5\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{8}{15}\div\dfrac{1}{3}\\x=-\dfrac{7}{5}\div\left(-2,5\right)\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{8}{5}\\x=\dfrac{14}{25}\end{matrix}\right.\)

13 tháng 10 2021

a: \(\dfrac{x}{0.9}=\dfrac{5}{6}\)

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

b: \(\dfrac{-6}{x}=\dfrac{9}{-15}\)

\(\Leftrightarrow x=10\)

c: \(\dfrac{\dfrac{14}{15}}{\dfrac{9}{10}}=\dfrac{x}{\dfrac{3}{7}}\)

\(\Leftrightarrow x=\dfrac{3}{7}\cdot\dfrac{14}{15}:\dfrac{9}{10}=\dfrac{2}{5}\cdot\dfrac{10}{9}=\dfrac{20}{45}=\dfrac{4}{9}\)

b) (5/2-3x)=25/9

            3x = 5/2-25/9

            3x =-5/18

              x =-5/18:3

              x=-5/54

\(e.\left(x-1\right)^5=-32\)

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

   \(x-1=-2\)

   \(x\)      \(=-2+1\)

   \(x\)        \(=-1\)

Vậy \(x=-1\)

9 tháng 7 2017

Ai chẳng biết chuyển vế đổi dấu :v

a) \(x-7=4x+10\)

\(x-4x=10+7\)

\(-3x=17\)

\(x=\dfrac{17}{-3}\)

Vậy \(x=\dfrac{17}{-3}\)

b) \(2x+5=-3x+7\)

\(2x+3x=7-5\)

\(5x=2\)

\(x=\dfrac{2}{5}\)

Vậy \(x=\dfrac{2}{5}\)

c) \(x-\left(3x+7\right)=6x-1\)

\(x-3x-7=6x-1\)

\(-2x-7=6x+1\)

\(-7-1=6x+2x\)

\(-8=8x\)

\(x=\dfrac{-8}{8}=-1\)

Vậy \(x=-1\)

d) \(x+\left(5x-1\right)=15\)

\(x+5x-1=15\)

\(6x=15+1\)

\(6x=16\)

\(x=\dfrac{16}{6}=\dfrac{8}{3}\)

Vậy \(x=\dfrac{8}{3}\)

9 tháng 7 2017

1 , x - 7 = 4x + 10

x - 4x = 10 + 7

- 3x = 17

x = 17 : ( - 3 )

x = \(\dfrac{-17}{3}\)

2 , 2x + 5 = -3x + 7

2x + 3x = 7 -5

5x = 2

x = 2 : 5

x =\(\dfrac{2}{5}\)

3 , x - ( 3x + 7 ) = 6x - 1

x - 3x - 7 = 6x - 1

x - 3x -6x = -1 +7

-8x = 6

x = 6 : ( -8 )

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

4 , x + ( 5x -1 ) = 15

x + 5x - 1 = 15

x + 5x = 15 + 1

6x = 16

x = 16 : 6

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

5 , / x + 1 / = / 2x - 5 /

TH 1 : x + 1 = 2x - 5

x - 2x = -5 -1

- x = -4

= > x = 4

TH 2 : -x -1 = -2x + 5

-x + 2x = 5 + 1

x = 6

6 , / 3x + 8 / - / x -10 / = 0

3x + 8 - x + 10 = 0

3x - x = 0 - 10 - 8

2 x = -18

x = -18 : 2

x = - 9

22 tháng 7 2021

a) 2x+8≤ 0 

⇔2x≤-8

⇔x≤-4

b) 4x-7 ≥ 2x -5

⇔2x-12 ≥ 0

⇔2x≥12

⇔x≥6

c) (2x-8)(15-3x)>0

TH1: 2x-8>0 ⇒x>4

        15-3x>0⇒x<5 

TH2:  2x-8<0 ⇒x<4

        15-3x<0⇒x>5 (vô lí)

vậy 4<x<5

27 tháng 6 2019

1) \(|5x-3|=|7-x|\)

\(\Leftrightarrow\orbr{\begin{cases}5x-3=7-x\\5x-3=x-7\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}6x=10\\4x=-4\end{cases}}\)

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

Vậy...

27 tháng 6 2019

2) \(2.|3x-1|-3x=7\)

\(\Leftrightarrow2.|3x-1|=7+3x\)

\(\Leftrightarrow\orbr{\begin{cases}2.\left(3x-1\right)=7+3x\\2.\left(3x-1\right)=-7-3x\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}6x-2=7+3x\\6x-2=-7-3x\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}3x=9\\9x=-5\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=\frac{-5}{9}\end{cases}}\)

Vậy...

a: \(=\left(1.25\right)^{16}\cdot8^{16}\cdot8=8\cdot10^{16}\)

b: \(=\left(\dfrac{5}{2}\right)^{13}\cdot4^{13}\cdot4^2=10^{13}\cdot4^2\)

c: \(=\left(0.25\right)^4\cdot8^4\cdot8^2=2^4\cdot8^2=64\cdot16=1024\)

d: \(=\left(\dfrac{1}{2}\right)^{15}\cdot2^{18}=2^3=8\)

e: \(=\left(\dfrac{1}{3}\cdot6\right)^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=2^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=\dfrac{1}{2}\)