b: Ta có: \(xy-3x-2y+6\)

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

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

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

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

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

c) = x^2(x + 3) - 7x(x + 3) + 9(x + 3)

= (x + 3)(x^2 - 7x + 9)

a: \(x^2-4xy+x-4y\)

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

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

b: \(x^2-6xy+9y^2-4\)

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

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

\(a,4x^2-4x+1\\ =\left(2x\right)^2-2.2x+1^2=\left(2x-1\right)^2\\ c,x^2-6xy-25z^2+9y^2\\ =\left(x^2-2.x.3y+9y^2\right)-\left(5z\right)^2\\ =\left(x-3y\right)^2-\left(5z\right)^2\\ =\left(x-3y-5z\right)\left(x-3y+5z\right)\)

Xem lại đề ý b

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

\(x^2-6xy-4z^2+9y^2=\left(x-3y\right)^2-\left(2z\right)^2=\left(x-3y-2z\right)\left(x-3y+2z\right)\)

b: Ta có: \(xy-3x-2y+6\)

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

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

c: Ta có: \(x^2-6xy+9y^2-4z^2\)

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

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

Em xem gõ lại đề cho đúng nha

`#\text {Kr.Ryo}`

`a)`

`4x^2 - 4x + 1`

`= (2x)^2 - 2*2x*1 + 1^2`

`= (2x - 1)^2`

`b)`

Xem lại đề

`c)`

`2x^2 + 7x + 5`

`= 2x^2 + 2x + 5x + 5`

`= (2x^2 + 2x) + (5x + 5)`

`= 2x(x + 1) + 5(x + 1)`

`= (2x + 5)(x + 1)`

`d)`

`x^2 - 6xy - 25z^2 + 9y^2`

`= (x^2 - 6xy + 9y^2) - 25z^2`

`= [ (x)^2 - 2*x*3y + (3y)^2] - (5z)^2`

`= (x + 3y)^2 - (5z)^2`

`= (x + 3y - 5z)(x + 3y + 5z)`

a: =5x(x-y)-7(x-y)

=(x-y)(5x-7)

b: =x(x+2y)+(x+2y)

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

c; =(x-3)^2-9y^2

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

a

\(5x^2-5xy+7y-7x\\ =5x\left(x-y\right)+7\left(y-x\right)\\ =5x\left(x-y\right)-7\left(x-y\right)\\ =\left(5x-7\right)\left(x-y\right)\)

b

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

c

\(x^2-6x-9y^2+9\\ =x^2-6x+9-\left(3y\right)^2\\ =x^2-2.x.3+3^2-\left(3y\right)^2\\ =\left(x-3\right)^2-\left(3y\right)^2\\ =\left(x-3-3y\right)\left(x-3+3y\right)\)

b: \(=\left(x-5\right)^2-9y^2\)

\(=\left(x-5-3y\right)\left(x-5+3y\right)\)

Bài 1: 

b: \(=\left(x-5\right)^2-9y^2\)

\(=\left(x-5-3y\right)\left(x-5+3y\right)\)