a) (3x - 1)³ + 17 = 710 : 5

(3x - 1)³ + 17 = 142

(3x - 1)³ = 142 - 17

(3x - 1)³ = 125

(3x - 1)³ = 5³

3x - 1 = 5

3x = 5 + 1

3x = 6

x = 6 : 3

x = 2

1. \(\frac{x-3}{x+2}=\frac{3}{4}\)

=> \(4(x-3)=3(x+2)\)

=> 4x - 12 = 3x + 6

=> 4x - 12 - 3x = 6

=> 4x - 3x - 12 = 6

=> x = 18

2. \(\frac{4-x}{x-1}=\frac{-5}{6}\)

=> 6[4 - x] = -5[x - 1]

=> 24 - 6x = 5 - 5x

=> 24 - 6x - 5 = 5x

=> 24 - 5 = 6x - 5x

=> 19 = x

=> x = 19

3. \(\frac{3-x}{-x+2}=\frac{-1}{3}\)

=> 3[3 - x] = -1[-x + 2]

=> 9 - 3x = x - 2

=> 9 - 3x + x = -2

=> 9 - 4x = -2

=> 4x = 9 - [ -2]

=> 4x = 9 + 2 = 11

=> x = 11/4

4. \(\frac{x-1}{12}=\frac{-3}{1-x}\)

=> [x-1][1-x] = -36

=> -[x-1]² = -36

=> [x-1]² = 36

=> [x-1]² = 6²

=> x -1 = 6 hoặc x - 1 = -6

=> x = 7 hoặc x = -5

5 . |x - 3 | - 8 = -4

=> |x - 3| = -4 + 8

=> |x - 3| = 4

=> x - 3 = 4 hoặc x - 3 = -4

=> x = 7 hoặc x = -1

Mấy bài sau tương tự

Chọn A

Lần sau bạn lưu ý ghi đầy đủ yêu cầu của đề nhé.

Lời giải:

a. $A=\left\{1; 2; 3;4 5; 6; 7\right\}$

b. $B=\left\{34; 36; 38; 40\right\}$
c. $B=\left\{9; 10; 11; 12; 13\right\}$
d. $B=\left\{25; 27; 29\right\}$

Ta có : 

\(3x=2y\)

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

ADTCDTSBN , ta có : 

\(\frac{x}{2}=\frac{y}{3}=\frac{2x}{4}=\frac{y-2x}{3-4}=\frac{5}{-1}=-5\)

\(\Rightarrow\hept{\begin{cases}\frac{x}{2}=-5\\\frac{y}{3}=-5\end{cases}\Rightarrow\hept{\begin{cases}x=-5.2=-10\\y=-5.3=-15\end{cases}}}\)

Vậy \(x=-10;y=-15\)

Bài 1: 

a: x/-2=-18/x

=>x²=36

=>x=6 hoặc x=-6

b: x/2+x/5=17/10

=>7/10x=17/10

hay x=17/7

\(x\cdot\dfrac{3}{7}-x\cdot\dfrac{1}{2}=\dfrac{3}{5}\)

\(x\left(\dfrac{3}{7}-\dfrac{1}{2}\right)=\dfrac{3}{5}\)

\(x\cdot\dfrac{-1}{14}=\dfrac{3}{5}\)

\(x=\dfrac{3}{5}:\dfrac{-1}{14}\)

\(x=\dfrac{-42}{5}\)

\(\left(\dfrac{6:\dfrac{3}{5}-\dfrac{17}{16}.\dfrac{6}{7}}{\dfrac{21}{5}.\dfrac{10}{11}+\dfrac{57}{11}}-\dfrac{\left(\dfrac{3}{20}+\dfrac{1}{2}-\dfrac{1}{15}\right).\dfrac{12}{49}}{\dfrac{10}{3}+\dfrac{2}{9}}\right).x=\dfrac{215}{96}\)

\(\Rightarrow\left(\dfrac{\dfrac{509}{56}}{9}-\dfrac{\dfrac{7}{12}.\dfrac{12}{49}}{\dfrac{32}{9}}\right).x=\dfrac{215}{96}\)

\(\Rightarrow\left(\dfrac{509}{504}-\dfrac{\dfrac{1}{7}}{\dfrac{32}{9}}\right).x=\dfrac{215}{96}\)

\(\Rightarrow\left(\dfrac{509}{504}-\dfrac{9}{224}\right).x=\dfrac{215}{96}\)

\(\Rightarrow\dfrac{1955}{2016}.x=\dfrac{215}{96}\)

\(\Rightarrow x=\dfrac{215}{96}:\dfrac{1955}{2016}\)

\(\Rightarrow x=\dfrac{903}{391}\)

`[ 6 : 3/5 - 17/16 . 6/7 : 21/5 . 10/11 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 :  10/3 + 2/9 ] . x = 215/96`

`=>[ 6  . 5/3 - 17/16 . 6/7 . 5/21 . 10/11 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`

`=>[10- 51/56 . 6/7 . 5/21 . 10/11 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`

`=> [10- 153/196  . 5/21 . 10/11 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`

`=> [10- 255/1372 . 10/11 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`

`=> [10- 1275/7546 + 57/11 -  (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`

`=> (10- 1275/7546 + 57/11 -  7/12. 12/49 . 3/10 + 2/9 ) . x = 215/96`

`=> ( 10- 1275/7546 + 57/11 -343/600 . 3/10 + 2/9 ) . x = 215/96`

`=> ( 10- 1275/7546 + 57/11 -343/2000 + 2/9 ) . x = 215/96`

`=>15,06357671 . x= 215/96`

`=> x= 215/96: 15,06357671`

`=>x= 0,1486754027`

Đề có phải như vậy không nhỉ ?

a)  5/17 * 8/-7+8/17*-7/3+-7/3*4/17

-40/119 + 12/17 × -7/3

-40/119 + -28/17 =-236/119

b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20

(5/17+12/17)-(10/13+3/13)-11/20

-11/20

a)  5/17 * 8/-7+8/17*-7/3+-7/3*4/17

-40/119 + 12/17 × -7/3

-40/119 + -28/17 =-236/119

b) -10/13 + 5/17 - 3/13 + 12/17 - 11/20

(5/17+12/17)-(10/13+3/13)-11/20

-11/20