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10 tháng 8 2017

Ta thấy:
\(12x^3+4x^2-27x-9\)
\(=12x^3-18x^2+22x^2-33x+6x-9\)
\(=6x^2\left(2x-3\right)+11x\left(2x-3\right)+3\left(2x-3\right)\)
\(=\left(6x^2+11x+3\right)\left(2x-3\right)\)
\(=\left(6x^2+9x+2x+3\right)\left(2x-3\right)\)
\(=\left[3x\left(2x+3\right)+\left(2x+3\right)\right]\left(2x-3\right)\)
\(=\left(3x+1\right)\left(2x+3\right)\left(2x-3\right)\)

\(a)\)

\(4x^2-y^2+2x+y\)

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

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

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

\(b)\)

\(x^3+2x^2-6x-27\)

\(=x^3+5x^2+9x-3x^2-15x-27\)

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

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

\(c)\)

\(12x^3+4x^2-27x-9\)

\(=\left(12x^3+4x^2\right)-\left(27x+9\right)\)

\(=4x^2\left(3x+1\right)-9\left(3x+1\right)\)

\(=\left(3x+1\right)\left(4x^2-9\right)\)

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

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

\(d)\)

\(16x^2+4x-y^2+y^2\)

\(=16x^2+4x\)

\(4x\left(4x+1\right)\)

24 tháng 10 2016

a) \(4x^2-8x+4-9\left(x-y\right)^2\)

\(=4\left(x^2-2x+1\right)-9\left(x-y\right)^2\)

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

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

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

b) \(x^3-4x^2+12x-27\)

\(=\left(x^3-27\right)-\left(4x^2-12x\right)\)

\(=\left(x-3\right)\left(x^2+3x+9\right)-4x\left(x-3\right)\)

\(=\left(x-3\right)\left(x^2-x+9\right)\)

5 tháng 8 2018

a) \(12x^3+8x^2-3x-2=4x^2\left(3x+2\right)-\left(3x+2\right)\)

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

b)  \(18x^3+27x^2-2x-3=9x^2\left(2x+3\right)-\left(2x+3\right)\)

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

c)  \(8x^3+4x^2-34x+15=4x^2\left(2x-3\right)+8x\left(2x-3\right)-5\left(2x-3\right)\)

\(=\left(2x-3\right)\left(4x^2+8x-5\right)=\left(2x-3\right)\left(2x-1\right)\left(2x+5\right)\)

3 tháng 8 2021

\(16y^2-4x^2-12x-9=16y^2-\left(2x-3\right)^2\)

\(=\left(4y-2x+3\right)\left(4y+2x-3\right)\)

3 tháng 8 2021

( 4y + 2x - 3 )

7 tháng 10 2019

a) \(x^3+6x^2+12x+8\)

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

b) \(x^3-3x^2+3x-1\)

\(=\left(x-1\right)^3\)

c) \(1-9x+27x^2-27x^3\)

\(=-\left(27x^3-27x^2+9x-1\right)\)

\(=-\left(3x-1\right)^3\)

7 tháng 10 2019

d) \(x^3+\frac{3}{2}x^2+\frac{3}{4}x+\frac{1}{8}\)

\(=\left(x+\frac{1}{2}\right)^3\)

e) \(27x^3-54x^2y+36xy^2-8y^3\)

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

4 tháng 1 2019

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

\(=x^4+3x^3+x^3+3x^2-5x^2-15x+3x+9\)

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

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

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

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

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

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

12 tháng 7 2015

x3-12x-4x2+27

=(x3+27)-(12x+4x2)

=(x+3)(x2-3x+9)-4x(x+3)

=(x+3)(x2-3x+9-4x)

=(x+3)(x2-7x+9)

28 tháng 9 2018

\(x^3-12x-4x^2+27\)

\(=x^3+3x^2-7x^2-21x+9x+27\)

\(=x^2\left(x+3\right)-7x\left(x+3\right)+9\left(x+3\right)\)

\(=\left(x+3\right)\left(x^2-7x+9\right)\)

4x^2−12x+9=(2x−3)^2

nha bạn 

4x2 - 12x + 9 = 

= ( 2x )2 - 2 . 2x . 3 + 32 

= ( 2x - 3 )2 

Hok tốt!!!!!!!!!!

19 tháng 8 2016

(x-3)(x^2-x+9)

19 tháng 8 2016

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cho

mk 

mk 

giải 

cho