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26 tháng 9 2017

(253-x):17-7=16

(253-x):17 = 16 +7

(253-x):17=23

253-x=23*17

253-x=391

x=253-391

x= -138

26 tháng 9 2017

\(\left(253-x\right):17-7=16\)

\(\left(253-x\right):17=16+7\)

\(\left(253-x\right):17=23\)

\(\left(253-x\right)=23.17\)

\(\left(253-x\right)=391\)

\(x=253-391\)

\(x=-138\)

Vậy \(x=-138\)

12 tháng 2 2018

\(5-x=17-\left(-5\right)\)

\(5-x=22\)

\(x=5-22\)

\(x=-17\)

a/ 5 - x = 17 - (-5) 

5-x = 22

x= -17

a: \(\Leftrightarrow x-3=-13\)

hay x=-10

d) Ta có: \(32\%-0.25:x=-\dfrac{17}{5}\)

\(\Leftrightarrow0.25:x=\dfrac{8}{25}+\dfrac{17}{5}=\dfrac{93}{25}\)

hay \(x=\dfrac{25}{372}\)

Vậy: \(x=\dfrac{25}{372}\)

e) Ta có: \(\left(x+\dfrac{1}{5}\right)^2+\dfrac{17}{25}=\dfrac{26}{25}\)

\(\Leftrightarrow\left(x+\dfrac{1}{5}\right)^2=\dfrac{9}{25}\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{5}=\dfrac{3}{5}\\x+\dfrac{1}{5}=-\dfrac{3}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{5}\\x=-\dfrac{4}{5}\end{matrix}\right.\)

Vậy: \(x\in\left\{\dfrac{2}{5};-\dfrac{4}{5}\right\}\)

f) Ta có: \(-\dfrac{32}{27}-\left(3x-\dfrac{7}{9}\right)^3=-\dfrac{24}{27}\)

\(\Leftrightarrow\left(3x-\dfrac{7}{9}\right)^3=\dfrac{-8}{27}\)

\(\Leftrightarrow3x-\dfrac{7}{9}=-\dfrac{2}{3}\)

\(\Leftrightarrow3x=\dfrac{1}{9}\)

hay \(x=\dfrac{1}{27}\)

g) Ta có: \(60\%\cdot x+0.4x+x:3=2\)

\(\Leftrightarrow\dfrac{4}{3}x=2\)

hay \(x=\dfrac{3}{2}\)

Vậy: \(x=\dfrac{3}{2}\)

h) PT \(\Leftrightarrow\left|\dfrac{20}{9}-x\right|=\dfrac{2}{9}\) \(\Rightarrow\left[{}\begin{matrix}\dfrac{20}{9}-x=\dfrac{2}{9}\\x-\dfrac{20}{9}=\dfrac{2}{9}\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{22}{9}\end{matrix}\right.\)

  Vậy ...

i) PT \(\Leftrightarrow\dfrac{8}{5}+\dfrac{2}{5}x=\dfrac{16}{5}\) \(\Leftrightarrow\dfrac{2}{5}x=\dfrac{8}{5}\) \(\Leftrightarrow x=4\)

  Vậy ...

 

14 tháng 2 2020

Tìm số nguyên x, biết:
1) -16 + 23 + x = - 16

7+x=-16

    x=-16-7

    x=-23
2) 2x – 35 = 15

2x=15+35

2x=50

  x=50:2

  x=25
3) 3x + 17 = 12

3x=12-17

3x=-5

  x=-5/3
4) (2x – 5) + 17 = 6

2x-5=6-17

2x-5=-11

2x=-11+5

2x=-6

  x=-6:2

  x=-3
5) 10 – 2(4 – 3x) = -4

2(4-3x)=10-(-4)

2(4-3x)=14

4-3x=14:2

4-3x=7

3x=4-7

3x=-3

  x=-3:3

  x=-1
6) - 12 + 3(-x + 7) = -18

3(-x+7)=-18-(-12)

3(x+7)=-6

x+7=-6:3

x+7=-2

    x=-2-7

    x=-9

tự đi mà làm

11 tháng 1 2016

a)15-(x-7)=-21

=>x-7=15-(-21)

=>x-7=15+21

=>x-7=36

=>x=36+7

=>x=43

b)(17-x)-12=16

=>17-x=16+12

=>17-x=28

=>x=17-28

=>x=-11

c)2x-35=15

=>2x=15+35

=>2x=50

=>x=50:2

=>x=25

d)3x+17=2

=>3x=2-17

=>3x=-15

=>x-15:3

=>x=-5

e)x-1=0

x=0+1

x=1

14 tháng 6 2015

x(5-12)+8(7-16)+12x-15(17-56)=0

​x.(-7)+8.(-9)+12x-15.(-39)=0

​x.(-7)+12x-72+585=0

​x(-7+12)+513=0

​x.5=-513

​x=-513/5