Mấy bài thực hiện phép tính bn tự làm nha

3.|x+4|-2.(x-1)=7-2x

3.|x-4|-2x-2=7-2x

=>2.|x-4|     =7-2x+2x+2

=>2.|x-4|     =9-4x

=>|x-4|        =4,5-2x

=>x-4=4,5-2x hoặc  x-4=-4,5+2x

  2+2x=4,5+4            4,5-4=2x-2

 3x     =8,5                0,5    =x

 x        =8,5:3

 x      =2,833

Vậy x\(\in\){2,833;0,5}

Phần còn lại bn làm tương tự nha

Chúc bn học tốt

1: Ta có: 7x+6(3-x)=27-20+73

\(\Leftrightarrow7x+18-6x=80\)

\(\Leftrightarrow x=80-18=62\)

Vậy: x=62

2: Ta có: \(6x-5\left(x-7\right)=\left(27-514\right)-486-73\)

\(\Leftrightarrow6x-5x+35=27-514-486-73\)

\(\Leftrightarrow x+35=-1046\)

\(\Leftrightarrow x=-1081\)

Vậy: x=-1081

 1) 9-25=(7-x)-(25+7)

(7-x)-(25+7)=9-25

(7-x)-(25+7)=-16

(7-x)-32=-16

7-x=-16+32

7-x=16

x=7-16

x=-9

2) (27-514) -(486-73)+x=7

 (27-514) -(486-73)+x=7

-487-413+x=7

-1011+x=7

x=7-(-1011)

x=7+1011

x=1018

3) 25+5+37-25+6-29-x=37

 25+5+37-25+6-29-x=37

67-25+6-29-x=37

42+6-29-x=37

48-29-x=37

19-x=37

x=19-37

x=-18

4) 14+(-12)+x =10-/-15/+ /-3/

14+(-12)+x =10-15+3

14+(-12)+x =-5+3

14+(-12)+x =-2

2+x=-2

x=-2-2

x=-4

1) - 9

2) 1018 

3) -18 

4) -4

tick nha

Ta có: \(6x-5.\left(x-7\right)=\left(27-514\right)-\left(486-73\right)\)

    \(\Leftrightarrow6x-5x+35=-487-413\)

   \(\Leftrightarrow x=-900-35\)

   \(\Leftrightarrow x=-935\)

Vậy \(x=-935\)

6x-5(x-7)=(27-514)-(486-73)
=>6x-5x+35=-487-413

=>x=-487-413-35

=>x=-935

vậy x=-935

2, 

a) \(315-\left(135-x\right)=215\)

\(\Rightarrow135-x=315-215\)

\(\Rightarrow135-x=100\)

\(\Rightarrow x=135-100\)

\(\Rightarrow x=35\)

b) \(x-320:32=25\cdot16\)

\(\Rightarrow x-10=5^2\cdot4^2\)

\(\Rightarrow x-10=20^2\)

\(\Rightarrow x-10=400\)

\(\Rightarrow x=410\)

c) \(3\cdot x-2018:2=23\)

\(=3\cdot x-1009=23\)

\(\Rightarrow3\cdot x=1032\)

\(\Rightarrow x=1032:3\)

\(\Rightarrow x=344\)

d) \(280-9\cdot x-x=80\)

\(\Rightarrow280-x\cdot\left(9+1\right)=80\)

\(\Rightarrow280-10\cdot x=80\)

\(\Rightarrow10\cdot x=280-80\)

\(\Rightarrow10\cdot x=200\)

\(\Rightarrow x=20\)

e) \(38\cdot x-12\cdot x-x\cdot16=40\)

\(\Rightarrow x\cdot\left(38-12-16\right)=40\)

\(\Rightarrow x\cdot10=40\)

\(\Rightarrow x=40:10\)

\(\Rightarrow x=4\)

bài 1 cậu ko giải giúp mình dc à

\(6x-5\left(x-7\right)=\left(27-514\right)-\left(486-73\right)\)

\(\Leftrightarrow6x-5x+35=27-514-486+73\)

\(\Leftrightarrow x=27-514-486+73-35\)

\(\Leftrightarrow x=-935\)

Đề bài : Tìm số nguyên x?

6x-5(x-7)=(27-514)-(486-73)

6x-5x+35=-900

x+35=-900

x=(-900)-35

x=-935

Vậy x=-935

\(\text{6x-5(x-7)=(27-514)-(486-73)}\)

\(6x-5\left(x-7\right)=27-514-486+73\)

\(6x-5\left(x-7\right)=\left(27+73\right)+\left(-514-486\right)\)

\(6x-5x+35=100+\left(-1000\right)\)

\(x+35=-900\)

\(\Rightarrow x=-900-35\)

\(\Rightarrow x=-935\)

học tốt

a) x(x - 5) - 4x + 20 = 0

\(\Leftrightarrow\) x(x - 5) - (4x + 20)

\(\Leftrightarrow\) x(x - 5) - 4(x - 5) = 0

\(\Leftrightarrow\) (x - 5)(x - 4)

Khi x - 5 = 0 hoặc x - 4 = 0

 \(\Leftrightarrow\) x = 5           \(\Leftrightarrow\) x = 4

 Vậy S = \(\left\{5;4\right\}\)

b) x(x + 6) - 7x - 42 = 0

 \(\Leftrightarrow\) x(x + 6) - (7x - 42) = 0

 \(\Leftrightarrow\) x(x + 6) - 7(x + 6) = 0

 \(\Leftrightarrow\) (x + 6)(x - 7) = 0

Khi x - 6 = 0 hoặc x - 7 = 0

   \(\Leftrightarrow\) x = 6           \(\Leftrightarrow\) x = 7

 Vậy S = \(\left\{6;7\right\}\)

c) x³ - 5x² - x + 5 = 0

 \(\Leftrightarrow\) (x³ - 5x²) - (x + 5) = 0

 \(\Leftrightarrow\) x² (x - 5) - (x - 5) = 0

 \(\Leftrightarrow\) (x - 5)(x² - 1) = 0

 \(\Leftrightarrow\) (x - 5)(x - 1)(x + 1) = 0

 Khi x - 5 = 0 hoặc x - 1 = 0 hoặc x + 1 = 0

   \(\Leftrightarrow\) x = 5           \(\Leftrightarrow\) x = 1            \(\Leftrightarrow\) x = -1

 Vậy S = \(\left\{5;1;-1\right\}\)

d) 4x² - 25 - (2x - 5)(3x + 7) = 0

\(\Leftrightarrow\) (2x)² - 5² - (2x - 5)(3x + 7) = 0

\(\Leftrightarrow\) (2x - 5)(2x + 5) - (2x - 5)(3x + 7) = 0

\(\Leftrightarrow\) (2x - 5) \([\left(2x+5\right)-\left(3x+7\right)]\) = 0

\(\Leftrightarrow\) (2x - 5) ( 2x + 5 - 3x + 7) = 0

\(\Leftrightarrow\) (2x - 5)( -x + 12) = 0

Khi 2x - 5 = 0 hoặc -x + 12 = 0

  \(\Leftrightarrow\) 2x = 5             \(\Leftrightarrow\)   -x = -12

  \(\Leftrightarrow\) x = \(\dfrac{5}{2}\)              \(\Leftrightarrow\) x = 12

 Vậy S = \(\left\{\dfrac{5}{2};12\right\}\)

e) x³ + 27 + (x + 3)(x - 9) = 0

\(\Leftrightarrow\) x³ - 3³ + (x + 3)(x - 9) = 0

\(\Leftrightarrow\) (x - 3)(x² - 3x + 9) + (x + 3)(x - 9) = 0

\(\Leftrightarrow\) (x - 3) \(\left[\left(x^2-3x+9\right)+\left(x-9\right)\right]\) = 0

\(\Leftrightarrow\) (x - 3) ( x² - 3x + 9 + x - 9) = 0

\(\Leftrightarrow\) (x - 3)(x² - 2x) = 0

\(\Leftrightarrow\) (x - 3)x(x - 2)

 Khi x - 3 = 0 hoặc x = 0 hoặc x - 2 = 0

    \(\Leftrightarrow\) x = 3                            \(\Leftrightarrow\) x = 2

 Vậy S = \(\left\{3;0;2\right\}\)

 Chúc bạn học tốt

a) Ta có: \(x\left(x-5\right)-4x+20=0\)

\(\Leftrightarrow\left(x-5\right)\left(x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=4\end{matrix}\right.\)

b) Ta có: \(x\left(x+6\right)-7x-42=0\)

\(\Leftrightarrow x\left(x+6\right)-7\left(x+6\right)=0\)

\(\Leftrightarrow\left(x+6\right)\left(x-7\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-6\\x=7\end{matrix}\right.\)

c) Ta có: \(x^3-5x^2-x+5=0\)

\(\Leftrightarrow\left(x-5\right)\left(x-1\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=1\\x=-1\end{matrix}\right.\)

d) Ta có: \(4x^2-25-\left(2x-5\right)\left(3x+7\right)=0\)

\(\Leftrightarrow\left(2x-5\right)\left(2x+5-3x-7\right)=0\)

\(\Leftrightarrow\left(2x-5\right)\left(x+2\right)=0\)

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