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

1D  2C

Câu 1: D

Câu 2: C

Ta có:\(4x\left(x-2y\right)-8y\left(x-2y\right)\)

\(=\left(x-2y\right)\left(4x-8y\right)\)

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

\(=\left(x-2y\right)^2.4\)

\(4x\left(x-2y\right)+8y\left(2y-x\right)\)

\(=4x\left(x-2y\right)-8\left(x-2y\right)\)

\(=\left(4x-8\right)\left(x-2y\right)\)

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

\(4x\left(x-2y\right)-8y\left(2y-x\right)\)

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

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

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

1.A

2.C

3.B

4.C

a

c

b

c

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

a: \(2y\left(x+2\right)-3x-6\)

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

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

b: \(3\left(x+4\right)-x^2-4x\)

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

\(=3\left(x+4\right)-x\left(x+4\right)\)

\(=\left(x+4\right)\left(3-x\right)\)

c: \(2\left(x+5\right)-x^2-4x\)

\(=2x+10-x^2-4x\)

\(=-x^2-2x+10\)

\(=-x^2-2x-1+11\)

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

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

\(=\left(\sqrt{11}-x-1\right)\left(\sqrt{11}+x+1\right)\)

d: \(x^2+6x-3x-18\)

\(=\left(x^2+6x\right)-\left(3x+18\right)\)

\(=x\left(x+6\right)-3\left(x+6\right)\)

\(=\left(x+6\right)\left(x-3\right)\)

\(x^6y+4x^2y\)

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

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

\(x^7y+x^5y+x^3y\)

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

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

A