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21 tháng 12 2020

5x(3x2-4x-1)=15x3-20x2-5x

                                        

30 tháng 7 2021

1, \(x^2\left(x-3\right)-4x+12=x^2\left(x-3\right)-4\left(x-3\right)\)

\(=\left(x-2\right)\left(x+2\right)\left(x-3\right)\)

2, \(2a\left(x+y\right)-x-y=2a\left(x+y\right)-\left(x+y\right)=\left(2a-1\right)\left(x+y\right)\)

3, \(2x-4+5x^2-10x=2\left(x-2\right)+5x\left(x-2\right)=\left(2+5x\right)\left(x-2\right)\)

4, sửa đề : 

 \(6x^2-12x-7x+14=6x\left(x-2\right)-7\left(x-2\right)=\left(6x-7\right)\left(x-2\right)\)

5, \(xy-y^2-3x+3y=y\left(x-y\right)-3\left(x-y\right)=\left(y-3\right)\left(x-y\right)\)

30 tháng 7 2021

a) x2(x-3)-4x+12

=x2(x-3)-4(x-3)

=(x-3)(x2-4)

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

b) 2a(x+y)-x-y

=2a(x+y)-(x+y)

=(x+y)(2a-1)

c) 2x-4+5x2-10x

=2(x-2)+5x(x-2)

=(x-2)(2+5x)

d) 5x2-12x-7x+14

=5x2-19x+14

e) xy-y2-3x+3y

=y(x-y)-3(x-y)

=(x-y)(y-3)

#H

24 tháng 12 2020

a.( 5x2-4x).(x-3)=5x3-15x2-4x2+12x=5x3-11x2+12x

b.(2-3xy).(3x4+4y2+5xy)=6x4+8y2+10xy-9x5y-12xy3-15x2y2

c.(-3x2+x+1).(x2+x-5)=-3x4-3x3+15+x3+x2-5x+x2+x-5=-3x4-2x3+2x-4x+10                                     

28 tháng 7 2017

a, \(5x^2-10xy+5y^2=5\left(x^2-2xy+y^2\right)=5.\left(x-y\right)^2\)

b, \(x^2-4x+4-y^2=\left(x^2-4x+4\right)-y^2=\left(x-2\right)^2-y^2\)

\(=\left(x-2-y\right)\left(x-2+y\right)\)

c, \(3x^2-2x-5=3x^2-5x+3x-5=x\left(3x-5\right)+3x-5\)

\(=\left(3x-5\right)\left(x+1\right)\)

24 tháng 12 2020

Bài 1: 

a) Ta có: \(\left(15x^2\cdot y^2\cdot z\right):3xyz\)

\(=\dfrac{15x^2y^2z}{3xyz}\)

\(=5xy\)

b) Ta có: \(3x^2\cdot\left(5x^2-4x+3\right)\)

\(=3x^2\cdot5x^2-3x^2\cdot4x+3x^2\cdot3\)

\(=15x^4-12x^3+9x^2\)

c) Ta có: \(\left(2x^2-3x\right):\left(x-4\right)\)

\(=\dfrac{2x^2-8x+5x-20+20}{x-4}\)

\(=\dfrac{2x\left(x-4\right)+5\left(x-4\right)+20}{x-4}\)

\(=2x+5+\dfrac{20}{x-4}\)

d) Ta có: \(-5xy\cdot\left(3x^2y-5xy+y^2\right)\)

\(=-5xy\cdot3x^2y+5xy\cdot5xy-5xy\cdot y^2\)

\(=-15x^3y^2+25x^2y^2-5xy^3\)

21 tháng 12 2023

`#3107`

`a.`

`4x^2 - 6x = 2x(2x - 3)`

`b.`

`9x^4y^3 + 3x^2y^4 = 3x^2y^2(3x^2y + y^2)`

`c.`

`x^3 - 2x^2 + 5x`

`= x(x^2 - 2x + 5)`

21 tháng 12 2023

a) 4x² - 6x

= 2x(2x - 3)

b) 9x⁴y³ + 3x²y⁴

= 3x²y³(3x² + 3y)

c) x³ - 2x² + 5x

= x(x² - 2x + 5)

a: Ta có: \(5\left(4x-1\right)+2\left(1-3x\right)-6\left(x+5\right)=10\)

\(\Leftrightarrow20x-5+2-6x-6x-30=10\)

\(\Leftrightarrow8x=43\)

hay \(x=\dfrac{43}{8}\)

b: ta có: \(2x\left(x+1\right)+3\left(x-1\right)\left(x+1\right)-5x\left(x+1\right)+6x^2=0\)

\(\Leftrightarrow2x^2+2x+3x^2-3-5x^2-5x+6x^2=0\)

\(\Leftrightarrow6x^2-3x-3=0\)

\(\Leftrightarrow2x^2-x-1=0\)

\(\Leftrightarrow\left(x-1\right)\left(2x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-\dfrac{1}{2}\end{matrix}\right.\)

9 tháng 9 2021

câu c,d đâu 

18 tháng 10 2023

a) \(x^2-5x+6\)

\(=x^2-2x-3x+6=x\left(x-2\right)-3\left(x-2\right)=\left(x-2\right)\left(x-3\right)\)

b) \(x^2-9x+18=x^2-3x-6x+18\)

\(=x\left(x-3\right)-6\left(x-3\right)=\left(x-3\right)\left(x-6\right)\)

c) \(x^2-6x+5=x^2-x-5x+5\)

\(=x\left(x-1\right)-5\left(x-1\right)=\left(x-1\right)\left(x-5\right)\)

d) \(3x^2+5x-30=3\left(x^2+\dfrac{5x}{3}-10\right)=3\left(x^2+2.x.\dfrac{5}{6}+\dfrac{25}{36}-\dfrac{5347}{500}\right)\)

Câu này bạn xem lại đề nha

e) \(3x^2-5x-2=3x^2-6x+x-2\)

\(3x\left(x-2\right)+x-2=\left(x-2\right)\left(3x+1\right)\)

 

 

6 tháng 8 2021

1, \(5x^2+10x+5-5y^2=5\left(x^2+2x+1-y^2\right)\)

\(=5\left[\left(x+1\right)^2-y^2\right]=5\left(x+1-y\right)\left(x+1+y\right)\)

2, \(3x^3+6x^2+3x-12xy^2=3x\left(x^2+2x+1-4y^2\right)\)

\(=3x\left[\left(x+1\right)^2-4y^2\right]=3x\left(x+1-2y\right)\left(x+1+2y\right)\)

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