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a: \(A=\left[111\cdot\left(38\cdot3-133\right)\right]\cdot2018\)

\(=111\cdot\left(-19\right)\cdot2018=-4255962\)

b: \(B=\left[25\left(1+3\cdot3-5\cdot2\right)\right]:20182019\)

\(=25\left(1+9-10\right):20182019=0\)

c: \(C=\dfrac{\left[244\left(395-195\right)\right]}{122\cdot200}=\dfrac{244}{122}=2\)

d: \(D=\dfrac{355\cdot45\cdot55}{11\cdot9\cdot7}=\dfrac{355\cdot5\cdot5}{7}=\dfrac{8875}{7}\)

1: \(=\dfrac{-\left[\left(x+5\right)^2-9\right]}{\left(x+2\right)^2}=\dfrac{-\left(x+5-3\right)\left(x+5+3\right)}{\left(x+2\right)^2}\)

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

2: \(=\dfrac{2x\left(x^2-4x+16\right)}{\left(x+4\right)\left(x^2-4x+16\right)}=\dfrac{2x}{x+4}\)

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

4: \(=\dfrac{3\left(x^2-4x+4\right)}{x\left(x^3-8\right)}=\dfrac{3\left(x-2\right)^2}{x\left(x-2\right)\left(x^2+2x+4\right)}\)

\(=\dfrac{3\left(x-2\right)}{x\left(x^2+2x+4\right)}\)

5: \(=\dfrac{2a\left(a-b\right)}{a\left(c+d\right)-b\left(c+d\right)}=\dfrac{2a\left(a-b\right)}{\left(c+d\right)\left(a-b\right)}=\dfrac{2a}{c+d}\)

6: \(=\dfrac{x\left(x-y\right)}{\left(x-y\right)\left(x+y\right)}\cdot\left(-1\right)=\dfrac{-x}{x+y}\)

7: \(=\dfrac{2\left(1-a\right)}{-\left(1-a^3\right)}=\dfrac{-2\left(1-a\right)}{\left(1-a\right)\left(1+a+a^2\right)}=-\dfrac{2}{1+a+a^2}\)

8: \(=\dfrac{x^4\left(x^3-1\right)}{\left(x^3-1\right)\left(x^3+1\right)}=\dfrac{x^4}{x^3+1}\)

9: \(=\dfrac{\left(x+2-x+2\right)\left(x+2+x-2\right)}{16x}=\dfrac{4\cdot2x}{16x}=\dfrac{1}{2}\)

10: \(=\dfrac{0.5\left(49x^2-y^2\right)}{0.5x\left(7x-y\right)}=\dfrac{1}{x}\cdot\dfrac{\left(7x-y\right)\left(7x+y\right)}{7x-y}\)

\(=\dfrac{7x+y}{x}\)

 

16 tháng 9 2017

Cau 1)

21+(x+23)=50

X+23=50-21

X=29-23

X=6

16 tháng 9 2017

Cau 2)

125+(x-100)=150

X-100=150-125

X=25+100

X=125

17 tháng 9 2018

a) 2x - 15 = 13

=> 2x = 13 + 15

=> 2x = 28

=>  x = 14

128 - (x + 5) = 23

=> x + 5 = 128 - 23

=> x + 5 = 105

=>  x = 105 - 5

=> x = 100

[(x2 + 54) - 32] . 2 = 244

=> (x2 + 54) - 32 = 244 : 2

=> (x2 + 54) - 32 = 122

=> x2 + 54 = 122 + 32

=> x2 + 54 = 154

=> x2 = 154 - 54

=> x2 = 100

=> x2 = 102

=> x = 10

(3x - 1)3 = 125

=> (3x - 1)3 = 53

=> 3x -  1 = 5

=> 3x = 5 + 1

=> 3x = 6

=> x = 2

17 tháng 9 2018

Bài 1: Tìm x biết

a, 2x - 15= 13             

 2x = 13 + 15 

2x = 28

x = 28 : 2

x = 14

Vậy x = 14

128 - (x + 5)= 23 

x + 5 = 128 - 23 

x + 5 = 105 

x = 105 - 5

x = 100

 Vậy x = 100       

 [( x2+54) - 32].2= 244   

\(x^2\) + 54 ) - 32 = 244 : 2

( x2+54) - 32 = 122

x2+54  = 122 + 32 

 x2+54 = 154

x2 = 154 - 54 

x2       = 100

\(x^2\) = \(10^2\)

x =10

(3x -1)3= 125

\(\left(3x-1\right)^3\) = \(5^3\)

3x -1 = 5

3x = 5 + 1 

x = 6 : 3 

x = 2

b, 100: ( 2x+5 )= 4     

2x + 5 = 100 : 4

2x + 5 = 25

2x = 45 - 5 

2x = 40

x = 40 : 2

x = 20     

 [( 8x-14 ) :2 - 2]. 31= 341   

( 8x - 14 ) : 2 - 1 = 341 : 31

( 8x - 14 ) :2 -2 = 11

( 8x - 14 ) : 2 = 11 + 2

( 8x - 14 ) : 2 = 13

8x - 14 = 13 . 2

8x - 14 = 26

8x = 26 + 14

8x = 40

x = 40 : 8

x = 5          

1230 :3 (x - 20 )= 10   

3 ( x - 20 ) = 1230 : 10

3 ( x - 20 ) = 123

x - 20 = 123 : 3

x- 20 = 41

x = 41 + 20 

x= 61

Câu cuối mk chịu

Tk mk nha

8 tháng 7 2023

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

|7 - \(\dfrac{3}{4}x\)|  - \(\dfrac{3}{2}\) = 2

|7 - \(\dfrac{3}{4}\)\(x\)| = 2 + \(\dfrac{3}{2}\)

|7 - \(\dfrac{3}{4}x\)| = \(\dfrac{7}{2}\)

\(\left[{}\begin{matrix}7-\dfrac{3}{4}x=\dfrac{7}{2}\\7-\dfrac{3}{4}x=-\dfrac{7}{2}\end{matrix}\right.\) 

\(\left[{}\begin{matrix}\dfrac{3}{4}x=7-\dfrac{7}{2}\\\dfrac{3}{4}=7+\dfrac{7}{2}\end{matrix}\right.\)

\(\left[{}\begin{matrix}\dfrac{3}{4}x=\dfrac{7}{2}\\\dfrac{3}{4}x=\dfrac{21}{2}\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=\dfrac{14}{3}\\x=14\end{matrix}\right.\)

8 tháng 7 2023

 5  - |\(x-3\)| = 5

       |\(x-3\)| = 5 - 5

      |\(x-3\)| = 0

      \(x-3\) = 0 

      \(x\) = 3

23 tháng 8 2023

4 x 2 x 5 = ?

Cách 1: 4 x 2 x 5 = (4 x 2) x 5 = 8 x 5 = 40

Cách 2: 4 x 2 x 5 = 4 x (2 x 5) = 4 x 10 = 40

 

7 x 2 x 3 = ?

Cách 1: 7 x 2 x 3 = (7 x 2) x 3 = 14 x 3 = 42

Cách 2: 7 x 2 x 3 = 7 x (2 x 3) = 7 x 6 = 42

 

6 x 3 x 3 = ?

Cách 1: 6 x 3 x 3 = (6 x 3) x 3 = 18 x 3 = 54

Cách 2: 6 x 3 x 3 = 6 x (3 x 3) = 6 x 9 = 54

 

6 x 2 x 4 = ?

Cách 1: 6 x 2 x 4 = (6 x 2) x 4 = 12 x 4 = 48

Cách 2: 6 x 2 x 4 = 6 x (2 x 4) = 6 x 8 = 48

21 tháng 10 2023

X+\(\dfrac{2}{7}\)=\(\dfrac{1}{2}\)

X     = \(\dfrac{1}{2}\)-\(\dfrac{2}{7}\)
X     = \(\dfrac{3}{14}\)
Chọn đáp án A. \(\dfrac{3}{14}\)

21 tháng 10 2023

A

12 tháng 11 2021

a: \(=\dfrac{2}{5}+\dfrac{3}{5}\cdot\dfrac{10}{3}\cdot\dfrac{1}{2}=\dfrac{2}{5}+\dfrac{10}{5}\cdot\dfrac{1}{2}=\dfrac{2}{5}+1=\dfrac{7}{5}\)

12 tháng 11 2021

phần b ạ

 

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

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