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

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

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

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

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

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

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

`x^2 -4x+4-y^2`

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

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

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

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

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

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

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

`x^2-2xy+y^2-9`

`=(x^2-2xy+y^2)-3^2`

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

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

Tách ra đi cậu.

a: \(=x\left(x-7y\right)+\left(x-7y\right)=\left(x-7y\right)\left(x+1\right)\)

x²-x-y²-y=(x²-y²)-(x+y)=(x-y)(x+y)-(x+y)=(x+y)(x-y-1)

x²-xy+x-y=x(x-y)+(x-y)=(x+1)(x-y)

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

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

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

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

\(x^2-11x+3\\ =\left(x^2-4x+4\right)-7x-1\\ =\left(x-2\right)^2-\left(\sqrt{7x+1}\right)^2\\ =\left(x-2-\sqrt{7x+1}\right)\left(x-2+\sqrt{7x+1}\right)\)

PHU HUYNH

\(=x^2+x-6x+6\\ =x\left(x+1\right)-6\left(x+1\right)\\ =\left(x+1\right)\left(x+6\right)\)

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

`x^2 - 3x - 4`

`<=> x(x - 3)-4`