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

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

\(2x^2+5x-3\\ =2x^2+6x-x-3\\ =2x\left(x+3\right)-\left(x+3\right)\\ =\left(x+3\right)\left(2x-1\right)\)

x 4 - 2 x 3 - 2 x 2 - 2 x - 3 =   ( x 4   −   1 )   −   ( 2 x 3   +   2 x 2 )   −   ( 2 x   +   2 ) =   ( x 2   +   1   ) ( x 2   −   1 )   −   2 x 2 ( x   +   1 )   − 2 ( x   +   1 ) =   ( x 2   +   1 ) ( x   −   1 ) ( x   +   1 )   −   2 x 2 ( x   +   1 )   − 2 ( x   +   1 ) =   ( x   +   1 ) ( x 2   +   1 ) ( x   −   1 )   −   2 x 2   –   2 =   ( x   +   1 ) (   x 2   +   1 ) ( x   −   1 )   −   2 ( x 2   +   1 ) =   ( x   +   1 ) (   x 2   +   1 ) ( x   –   1   −   2 ) =   ( x   +   1 ) (   x 2   +   1 ) ( x   −   3 )

x^4 - 2x^3 - 2x^2 - 2x - 3 

= x^4 - 1 - 2x^3 - 2x^2 - 2x -2 

= ( x - 1 ) ( x + 1 ) ( x^2 + 1 ) - 2x^2 ( x + 1 ) - 2 ( x + 1 ) 

= ( x + 1 ) [ ( x - 1 ) ( x^2 + 1 ) - 2x^2 - 2 ] 

= ( x + 1 ) [ ( x - 1 ) ( x^2 + 1 - 2 ( x^2 - 1 ) ] 

= ( x + 1 ) [ ( x - 1 ) ( x^2 + 1 ) - 2 ( x - 1 ) ( x + 1 ) ] 

= ( x + 1 ) ( x - 1 ) [ ( x^2 + 1 ) - 2 ( x +1 ) 

= ( x + 1 ) ( x - 1 ) ( x^2 +1 - 2x - 2 ) 

= ( x + 1 ) ( x - 1 ) ( x^2 - 2x - 1 ) 

\(=\left(2x^2+xy-3x\right)-\left(22xy+11y^2-33y\right)+\left(2x+y-3\right)\)

\(=x\left(2x+y-3\right)-11y\left(2x+y-3\right)+\left(2x+y-3\right)\)

\(=\left(x-11y+1\right)\left(2x+y-3\right)\)

x4 – 2x2

(Có x2 là nhân tử chung)

= x2(x2 – 2)

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

1: \(-x^2+2x+8\)

\(=-\left(x^2-2x-8\right)\)

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

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

a) 2x²- 6x²

= -4x²

b) x²-6x+9-y²

= (x-3)² -y²

= (x-3-y).(x-3+y)

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

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

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