`a)x-xy +y-y^2`
`=x(1-y)+y(1-y)`
`=(1-y)(x+y)`
`b)x^2 -4x -y^2 +4`
`=(x^2 -4x+4)-y^2`
`=(x-2)^2 -y^2`
`=(x-2-y)(x-2+y)`
`c)x^2 - 2x -3`
`=x^2 +x -3x -3`
`=x(x+1)-3(x+1)`
`=(x+1)(x-3)`
\(x-xy+y-y^2=x\left(1-y\right)+y\left(1-y\right)=\left(1-y\right)\left(x+y\right)\)
\(x^2-4x-y^2+4=\left(x-2\right)^2-y^2=\left(x-2-y\right)\left(x-2+y\right)\)
\(x^2-2x-3=x^2+x-3x-3=x\left(x+1\right)-3\left(x+1\right)=\left(x+1\right)\left(x-3\right)\)
a)
\(x-xy+y-y^2\)
\(=x\left(1-y\right)+y\left(1-y\right)\)
\(=\left(1-y\right)\left(x+y\right)\)
b)
\(x^2-4x-y^2+4=\left(x^2-4x+4\right)-y^2=\left(x-2\right)^2-y^2=\left(x-2-y\right)\left(x-2+y\right)\)
c)
\(x^2-2x-3=x^2-3x+x-3=x\left(x-3\right)+\left(x-3\right)=\left(x-3\right)\left(x+1\right)\)
