\(1,=x\left(x^2-2x+1-y^2\right)=x\left[\left(x-1\right)^2-y^2\right]=x\left(x-y-1\right)\left(x+y-1\right)\\ 2,=\left(x+y\right)^3\\ 3,=\left(2y-z\right)\left(4x+7y\right)\\ 4,=\left(x+2\right)^2\\ 5,Sửa:x\left(x-2\right)-x+2=0\\ \Leftrightarrow\left(x-2\right)\left(x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)

^2 + 4xy - 16 + 4y^2 
= x^2 + 4xy + 4y^2 - 4^2 
= (x + 2y)^2 - 4^2 
= (x + 2y - 4)(x + 2y + 4) 
2x^2-5xy-3y^2 
= 2^x + xy - 6xy - 3y^2 
= x(2x + y) - 3y(2x + y) 
= (2x + y)(x - 3y)

mình chưa hiểu

1.A

2.C

3.B

4.C

a

c

b

c

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

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

3) \(xy\left(x+y\right)-x-y=xy\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(xy-1\right)\) (xem lại đề sửa -2x thành -x mới đúng)

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

`a^3-a^2 x -ay+xy`

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

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

`x^2-2xy+x-2y`

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

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

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

`x^2-2x+2y-xy`

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

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

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

1,(a^2-y)(a-x)

x³ + 2x²y + xy² - 9x

= x( x² + 2xy + y² - 9 )

= x[ ( x² + 2xy + y² ) - 9 ]

= x[ ( x + y )² - 3² ]

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

Bài làm 

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

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

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

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

x(x+y)-2(x+y)

(x-2)(x+y)

Ý a có rì đó sai sai nha bn 

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