1.(x+2)(x² -2x+4)

=(x+2)(x-2)²

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

=x-2

1.(x+2)(x²-2x+4)

=x³+8

1D  2C

Câu 1: D

Câu 2: C

=(x^2-2xy+y^2)-(3x-3y)+2

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

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

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

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

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

3x - 3y + x² - y² 

= (3x - 3y) + (x² - y²)

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

=(3 + x + y)(x - y)

`x^2-y^2-3x+3y`

`=(x^2-y^2) -(3x-3y)`

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

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

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

Lời giải:

1. 
$x^3+3x^2-16x-48=(x^3+3x^2)-(16x+48)=x^2(x+3)-16(x+3)$

$=(x+3)(x^2-16)=(x+3)(x-4)(x+4)$

2.

$4x(x-3y)+12y(3y-x)=4x(x-3y)-12y(x-3y)=(x-3y)(4x-12y)=4(x-3y)(x-3y)=4(x-3y)^2$

3.

$x^3+2x^2-2x-1=(x^3-x^2)+(3x^2-3x)+(x-1)=x^2(x-1)+3x(x-1)+(x-1)$

$=(x-1)(x^2+3x+1)$

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

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