\(a,\left(x+2\right)^2+\left(x+3\right)^2-2\left(x-2\right)\left(x-3\right)=19\\ \Leftrightarrow x^2+4x+4+x^2+6x+9-2x^2+10x-12=19\\ \Leftrightarrow20x=20\\ \Leftrightarrow x=1\\ b,\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2-5\right)=15\\ \Leftrightarrow x^3+8-x^3+5x=15\\ \Leftrightarrow5x=7\\ \Leftrightarrow x=\dfrac{7}{5}\\ c,\left(x-1\right)^3+\left(2-x\right)\left(4+2x+x^2\right)+3x\left(x+2\right)=17\\ \Leftrightarrow x^3-3x^2+3x+1+8-x^3+3x^2+6x=17\\ \Leftrightarrow9x=8\\ \Leftrightarrow x=\dfrac{8}{9}\)

a. (x + 2)² + (x + 3)² - 2(x - 2)(x - 3) = 19

<=> (x² + 4x + 4) + (x² + 6x + 9) - (2x + 4)(x - 3) = 19

<=> x² + 4x + 4 + x² + 6x + 9 - 2x² + 6x - 4x + 12 = 19

<=> x² + x² - 2x² + 4x + 6x + 6x - 4x + 9 + 4 + 12 - 19 = 0

<=> 12x + 6 = 0

<=> 6(2x + 1) = 0

<=> 2x + 1 = 0

<=> 2x = -1

<=> x = \(\dfrac{-1}{2}\)  

b. (x + 2)(x² - 2x + 4) - x(x² - 5) = 15

<=> x³ - 2x² + 4x + 2x² - 4x + 8 - x³ + 5x - 15 = 0

<=> x³ - x³ - 2x² + 2x² + 4x - 4x + 5x + 8 - 15 = 0

<=> 5x - 7 = 0

<=> 5x = 7

<=> x = \(\dfrac{7}{5}\)

a: \(\Leftrightarrow x+3\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)

hay \(x\in\left\{-2;-4;-1;-5;0;-6;1;-7;3;-9;9;-15\right\}\)

x=15 và x=-9 bạn nhé

a) \(\dfrac{x}{5}=\dfrac{2}{5}\)

\(\Rightarrow5x=10\)

\(\Leftrightarrow x=2\)

Vậy x = 2

b) ĐKXĐ: \(x\ne0\)

 \(\dfrac{3}{-8}=\dfrac{6}{-x}\)

\(\Rightarrow-3x=-48\)

\(\Leftrightarrow x=16\)

Vậy x = 16

c) \(\dfrac{1}{9}=\dfrac{-2x}{10}\)

\(\Rightarrow-18x=10\)

\(\Leftrightarrow x=-\dfrac{5}{9}\)

Vậy \(x=-\dfrac{5}{9}\)

d) ĐKXĐ: \(x\ne0\)

 \(\dfrac{3}{x}-5=\dfrac{-9}{x}+2\)

\(\Leftrightarrow\dfrac{3-5x}{x}=\dfrac{-9+2x}{x}\)

\(\Rightarrow3-5x=-9+2x\)

\(\Leftrightarrow7x=12\)

\(\Leftrightarrow x=\dfrac{12}{7}\)

Vậy \(x=\dfrac{12}{7}\)

e) ĐKXĐ: \(x\ne0\)

 \(\dfrac{x}{-2}=\dfrac{-8}{x}\)

\(\Rightarrow x^2=16\)

\(\Leftrightarrow x=\pm4\)

Vậy \(x=\pm4\)

a) Ta có: \(\dfrac{x}{5}=\dfrac{2}{5}\)

\(\Leftrightarrow x=\dfrac{2\cdot5}{5}=2\)

Vậy: x=2

b) Ta có: \(\dfrac{3}{-8}=\dfrac{6}{-x}\)

\(\Leftrightarrow-x=\dfrac{6\cdot\left(-8\right)}{3}=-16\)

hay x=16

Vậy: x=16

1) x - 2 = -6

x = - 6 + 2

x = -4

2) -5x-(-3)=13

-5x+3=13

-5x=13-3=10

x=10:(-5)

x=-2

3) 15-(x-7)=21

15-x+7=21

15-x=21-7=14

x=15-14=1

4) 3x+17=2

3x=2-17=-15

x=-15:3=-5

5) 45-(x-9)=-35

45-x+9=-35

45-x=-35-9=-44

x=45-(-44)=89

6) -5+x=15

x=15-(-5)

x=20

7) 2x-(-17)=15

2x+17=15

2x=15-17=-2

x=-2:2=-1

ai giúp mk câu này với

8) \(\left|x-2\right|=3\\ \Rightarrow x-2=\pm3\)

+) x - 2 = 3

x = 5

+) x - 2 = -3

x = -1

\(\Rightarrow x\in\left\{5;-1\right\}\)

Các câu 9; 10; 12 tương tự câu 8; còn câu 11 tương tự câu 3; 5

Chúc bạn học tốt!

A

A

A

a) x-12=-9+15

     x-12=24

     x=24+12

     x=36

Vậy x=36

b)4x -12=400

    4x=412

    x=412:4

   x=103

Vậy x=103

c)2x -35=15

   2x=50

   x=50:2

   x=15

Vậy x=15

d)3x+17=2

   3x=-15

   x=(-15):3

  x=-5

Vậy x=-5

e)\(\frac{-5}{8}=\frac{x}{16}\)

\(\Rightarrow\left(-5\right).16=8.x\)

\(\Rightarrow8x=-80\)

\(\Rightarrow x=-10\)

f)\(\frac{y}{10}=-\frac{4}{8}\)

\(\Rightarrow8y=\left(-4\right).10\)

\(\Rightarrow8y=-40\)

\(\Rightarrow y=-5\)

a) x - 12 = -9 + 15 

=> x - 12 = 6 

=> x = 6 + 12 = 18

b) 4x - 12 = 400 

=> 4x = 400 + 12 = 412

=> x = 412 : 4 = 103

c) 2x - 35 = 15

=> 2x = 15 + 35 = 50

=> x = 50 : 2 = 25

d) 3x + 17 = 2

=> 3x = 2 - 17 

=> 3x = -15

=> x = -15 : 3 = -5

e) \(\frac{-5}{8}=\frac{x}{16}\)

\(=>\frac{-10}{16}=\frac{x}{16}\)

=> x = -10

f) \(\frac{y}{10}=\frac{-4}{8}\)

\(=>\frac{y}{10}=\frac{-1}{2}\)

\(=>\frac{y}{10}=\frac{-5}{10}\)

=> y = -5

a) x - 12 = -9 + 15

x - 12 = 6

x = 12 + 6

x = 18

b) 4x - 12 = 400

4x = 412 

x = 412 : 4

x = 103

c) 2x - 35 = 15

2x = 50

=> x = 25 

d) 3x + 17 = 2

=> 3x = -15

=> x = -5

e) -5/8 = x/16

=> -10/16 = x/16

=> x = -10

y/10 = -4/8

=> y/10 = -40/80

=> y/10 = -5/10

=> y = -5

tìm giá trị của x để biểu thức nhận giá trị âm nhé

Câu tính bn vít lại đề ik, khó hỉu wa

2) a. x² + 5x = x.(x + 5) âm

=> x.(x + 5) < 0

=> x và x + 5 trái dấu

Mà x < x + 5

=> x < 0; x + 5 > 0

=> x < 0; x > -5

=> x thuộc {-4 ; -3; -2; -1}

b. 3.(2x + 3).(3x - 3)

= 3.(2x + 3).3.(x - 1)

= 9.(2x + 3).(x - 1) âm

=> 9.(2x + 3).(x - 1) < 0

=> (2x + 3).(x - 1) < 0

=> (2x + 3).(2x - 2) < 0

Mà 2x + 3 > 2x - 2

=> 2x + 3 > 0; 2x - 2 < 0

=> 2x > -3; 2x < 2

=>x > -3/2; x < 1

=> x > -2; x < 1

=> x thuộc {-1; 0}

\(\left(\left(\frac{2}{193}-\frac{3}{386}\right).\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{7}{1931}+\frac{11}{3862}\right).\frac{1935}{25}+\frac{9}{2}\right)\)

\(=\left(\left(\frac{4}{386}-\frac{3}{386}\right)\frac{193}{17}+\frac{33}{34}\right):\left(\left(\frac{14}{3862}+\frac{11}{3862}\right).\frac{1935}{25}+\frac{9}{2}\right)\)

\(=\left(\frac{1}{386}.\frac{193}{17}+\frac{33}{34}\right):\left(\frac{25}{3862}.\frac{1935}{25}+\frac{9}{2}\right)\)

\(=\left(\frac{1}{34}+\frac{33}{34}\right):\left(\frac{1}{2}+\frac{9}{2}\right)\)

\(=1:\frac{10}{2}=1.\frac{1}{5}=\frac{1}{5}\)