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

2x²+4x+xy+2y

= 2x(x+2)+y(x+2)

= (x+2)(2x+y)

1D  2C

Câu 1: D

Câu 2: C

\(a,2x+2y-x^2-xy=2x+2y-\left(x^2+xy\right).\)

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

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

\(a,2x+2y-x^2-xy=2.\left(x+y\right)-x.\left(x+y\right)=\left(2-x\right).\left(x+y\right)\)

\(b,4x^3+9x^2-19x-30=3x^3+x^3+9x^2-9x-10x-30\)

\(=3x^2.\left(x+3\right)+x.\left(x-3\right).\left(x+3\right)-10.\left(x+3\right)=\left(x+3\right).\left(3x^2+x^2-3x-10\right)\)

1.A

2.C

3.B

4.C

a

c

b

c

(x-1)y^2-4(x-1)y

4x²+8x+xy+2y

<-> 4x(x+2)+y(x+2)

<-> (x+2)(4x+y)

\(4x^2+8x+xy+2y\)

\(=\left(4x^2+8x\right)+\left(xy+2y\right)\)

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

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

Ph ntu 

15(x-y) - 20x ( y-x)

x³ + 2x²y + xy² - 4x

= x( x² + 2xy + y² - 4 )

= x[ ( x + y )² - 2² ]

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

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

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

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

a) x^ 3 + 2x^ 2y + xy ^2 − 4x

= x (x^ 2 + 2xy + y^ 2 − 4)

= x [(x + y)^ 2 − 2 ^2]

= x (x + y + 2)(x + y − 2)