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26 tháng 8 2022

a) 30x-3x = 5 . 54

=> 27x = 270

=> x = 10

b) 15x-9x + 2x = 7

=> 8x = 7

\(\Rightarrow x=\dfrac{7}{8}\)

26 tháng 8 2022

30x - 3x = 5 . 54

= x . ( 30 - 3 ) = 270

= x .27 = 270

= x = 270 : 27

= x = 10

 

15x - 9x + 2x = 7

= x . ( 15 - 9 + 2 ) = 7

= x . 8 = 7

= x = 7/8

14 tháng 10 2020

6) \(9x^3y^2+3x^2y^2=3x^2y^2\left(3x+1\right)\)

7) \(x^3+2x^2+3x=x\left(x^2+2x+3\right)\)

8) \(6x^2y+4xy^2+2xy=2xy\left(3x+2y+1\right)\)

9) \(5x^2\left(x-2y\right)-15x\left(x-2y\right)=5x\left(x-2y\right)\left(x-3\right)\)

10) \(3\left(x-y\right)-5x\left(y-x\right)=\left(x-y\right)\left(3+5x\right)\)

14 tháng 10 2020

6) 9x3y2 + 3x2y2 = 3x2y2( 3x + 1 )

7) x3 + 2x2 + 3x = x( x2 + 2x + 3 )

8) 6x2y + 4xy2 + 2xy = 2xy( 3x + 2y + 1 )

9) 5x2( x - 2y ) - 15x( x - 2y ) = 5x( x - 2y )( x - 3 )

10 3( x - y ) - 5x( y - x ) = 3( x - y ) + 5x( x - y ) = ( x - y )( 3 + 5x )

a: 3x-2=2x-3

=>x=-1

b: 2x+3=5x+9

=>-3x=6

=>x=-2

c: 5-2x=7

=>2x=-2

=>x=-2

d: 10x+3-5x=4x+12

=>5x+3=4x+12

=>x=9

e: 11x+42-2x=100-9x-22

=>9x+42=78-9x

=>18x=36

=>x=2

f: 2x-(3-5x)=4(x+3)

=>2x-3+5x=4x+12

=>7x-3=4x+12

=>3x=15

=>x=5

5 tháng 9 2017

(6x+1)(2x-5)=12x2-30x+2x-5=12x2-28x-5

(2x+5)2-2x(2x+8)=4x2+20x+25-4x2-16x=4x+25

(3x-5)(2x-1)-(2x+3)(3x+7)+30x=6x2-3x-10x+5=6x2-13x+5

(X-1)2-(x+1)(x-1)=x2-2x+1-x2+1=-2x+2

(3x+2)(9x2-6x+4)-(3+x)(x-3)=27x3+8+9-x2=27x3-x2+17

30 tháng 9 2019

\(\frac{2x-1}{3x^2+7x+2}+\frac{3}{9x^2+15x+4}-\frac{2x+7}{3x^2-5x-12}=\frac{5}{x+2}\)

\(\Leftrightarrow\frac{2x-1}{\left(3x+1\right)\left(x+2\right)}+\frac{3}{\left(3x+1\right)\left(3x+4\right)}-\frac{2x+7}{\left(4x+3\right)\left(x-3\right)}=\frac{5}{\left(x+2\right)}\)

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

\(\Leftrightarrow\frac{1}{x+2}-\frac{1}{x-3}=\frac{5}{x+2}\)

\(\Leftrightarrow\frac{x-3-x-2}{\left(x+2\right)\left(x-3\right)}=\frac{5\left(x-3\right)}{\left(x+2\right)\left(x-3\right)}\)

\(\Leftrightarrow5x-3=-5\)

\(\Leftrightarrow x=-\frac{2}{5}\)

Chúc bạn học tốt !!!

23 tháng 7 2019

a) \(x^2-10x+25-36\) 

  \(=\left(x-5\right)^2-6^2\) 

\(=\left(x-5+6\right)\left(x-5-6\right)=\left(x+1\right)\left(x-11\right)\) 

b) \(2x^2+22\) 

\(=2\left(x^2+11\right)\) 

23 tháng 7 2019

a) C1: x- 10x - 11 = (x2 - 2.x.5 + 25) - 36

                               = (x - 5)2 - 62

                               = (x - 11)(x + 1)

    C2: x2 - 10x - 11 = x2 + x - 11x - 11 

                               = x(x + 1) - 11(x + 1)

                               = (x - 11)(x + 1)

HQ
Hà Quang Minh
Giáo viên
15 tháng 9 2023

\(2x^4-8x^3-7x^3+28x^2+7x^2-28x-2x+8\\ =2x^3\left(x-4\right)-7x^2\left(x-4\right)+7x\left(x-4\right)-2\left(x-4\right)\\ =\left(x-4\right)\left(2x^3-7x^2+7x-2\right)\\ =\left(x-4\right)\left(2x^3-4x^2-3x^2+6x+x-2\right)\\ =\left(x-4\right)\left[2x^2\left(x-2\right)-3x\left(x-2\right)+\left(x-2\right)\right]\\ =\left(x-4\right)\left(x-2\right)\left(2x^2-2x-x+1\right)\\ =\left(x-4\right)\left(x-2\right)\left(2x-1\right)\left(x-1\right)\)

3 tháng 10 2023

a) \(\dfrac{x^2+2x}{A}=\dfrac{x}{3}\)

\(\Rightarrow A=\dfrac{\left(x^2+2x\right)\cdot3}{x}\)

\(\Rightarrow A=\dfrac{x\left(x+2\right)\cdot3}{x}\)

\(\Rightarrow A=3x+6\)

b) \(\dfrac{A}{3x-2}=\dfrac{15x^2+10x}{9x^2-4}\)

\(\Rightarrow A=\dfrac{\left(3x-2\right)\left(15x^2+10x\right)}{9x^2-4}\)

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

\(\Rightarrow A=\dfrac{5x\left(3x+2\right)\left(3x-2\right)}{\left(3x+2\right)\left(3x-2\right)}\)

\(\Rightarrow A=5x\)

1 tháng 1 2019

\(\dfrac{2x-1}{3x^2+7x+2}+\dfrac{3}{9x^2+15x+4}-\dfrac{2x+7}{3x^2-5x-12}=\dfrac{5}{x+2}\)

\(\Leftrightarrow\dfrac{2x-1}{\left(3x+1\right)\left(x+2\right)}+\dfrac{3}{\left(3x+1\right)\left(3x+4\right)}-\dfrac{2x+7}{\left(4x+3\right)\left(x-3\right)}=\dfrac{5}{x+2}\)

\(\Leftrightarrow\dfrac{1}{x+2}-\dfrac{1}{3x+1}+\dfrac{1}{3x+1}-\dfrac{1}{3x+4}+\dfrac{1}{3x+4}-\dfrac{1}{x-3}=\dfrac{5}{x+2}\)

\(\Leftrightarrow\dfrac{1}{x+2}-\dfrac{1}{x-3}=\dfrac{5}{x+2}\)

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

\(\Leftrightarrow5x-3=-5\)

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

Vậy...

1 tháng 1 2019

tks bạn