\(=\left(12x^2-18xy+9x\right)+\left(8xy-12y^2+6y\right)-\left(4x-6y+3\right)\)

\(=3x\left(4x-6y+3\right)+2y\left(4x-6y+3\right)-\left(4x-6y+3\right)\)

\(=\left(4x-6y+3\right)\left(3x+2y-1\right)\)

Sửa đề: 12x² + 5x - 12y² + 12y - 10xy - 3 

= -(12x² + 10xy + 3 -12x² - 5x - 12y)

Có

12y² + 10xy + 3 - 12x² - 5x - 12y

= 18xy + 12y² - 6y - 12x² - 8xy + 4x - 9x - 6y + 3

= 6y (3x + 2y - 1) - 4 . x (3x + 2y - 1) - 3 . (3x + 2y - 1) 

= (6y - 4x - 3) . (3x + 2y - 1)

12x² + 5x - 12y² + 12y - 10xy - 3 

= -(12x² + 10xy + 3 -12x² - 5x - 12y)

Có

12y² + 10xy + 3 - 12x² - 5x - 12y

= 18xy + 12y² - 6y - 12x² - 8xy + 4x - 9x - 6y + 3

= 6y (3x + 2y - 1) - 4 . x (3x + 2y - 1) - 3 . (3x + 2y - 1) 

= (6y - 4x - 3) . (3x + 2y - 1)

12x² + 5x - 12y² + 12y - 10xy - 3 

= -(12x² + 10xy + 3 -12x² - 5x - 12y)

Có

12y² + 10xy + 3 - 12x² - 5x - 12y

= 18xy + 12y² - 6y - 12x² - 8xy + 4x - 9x - 6y + 3

= 6y (3x + 2y - 1) - 4 . x (3x + 2y - 1) - 3 . (3x + 2y - 1) 

= (6y - 4x - 3) . (3x + 2y - 1)

=12(x+(2x-1)/3)(x-(6x-3)/4)

12(x+(2x-1)/3)(x-(6x-3)/4))

a/  2x^3 -5x^2 + 8x -3

= 2x^3 -x^2 -4x^2 +2x +6x -3

= x^2 .[2x-1] - 2x[2x-1] +3. [2x-1]

= [x^2-2x+3] [2x-1]

b/  3x^3 - 14x^2 +4x +3 

= 3x^3 +x^2 -15 x^2 -5x +9x +3

= x^2 [3x+1] -5.x [3x+1] +3. [3x+1]

= [x^2 -5x+3] [3x+1]

c/  Đặt C =  12x^2 + 5 x -12 y^2 +12y -10xy -3

 = -[12y^2+10xy+3-12x^2-5x-12y]

12y^2 + 10xy +3-12x^2-5x-12y = 18xy +12y^2 -6y - 12x^2 -8xy +4x -9x -6y +3

                                             = 6y [3x+2y-1] - 4.x[3x+2y-1] -3.[3x+2y-1]

                                            = [6y-4x-3] [3x+2y-1]

=> C = -[6y-4x-3]. [ 3x+2y-1]

tom lai minh ra

12x²+5x-12y²+12y-10xy-3=12(x+(2y-1)/3)(x-(6y-3)/4)) co dung ko nha.