1: =(16x^2-8x+1)-y^2

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

=(4x-1-y)(4x-1+y)

2: =(x^2-2xy+y^2)-z^2

=(x-y)^2-z^2

=(x-y-z)(x-y+z)

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

=(x+2y)^2-4^2

=(x+2y-4)(x+2y+4)

4: =(x^2-4xy+4y^2)-16

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

=(x-2y-4)(x-2y+4)

Đề sai nhé .Sửu lại

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

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

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

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

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

\(=\left(2x\right)^2-2\cdot2x\cdot y+y^2\)

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

\(---\)

\(\left(x+1\right)^2-9y^2\)

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

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

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

\(---\)

\(2x+5^2-9x^2\) (kt lại đề bài)

\(2x-1^2-3x-1^2\)

\(=-x-2=-1\cdot\left(x+2\right)\)

1.A

2.C

3.B

4.C

a

c

b

c

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

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

b: =x(x^2-2x+1+4y^2)