Bài 1:
1: \(x^2-y^2-2x+2y\)
\(=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)\)
=(x-y)(x+y-2)
2: \(xy-5y+2x-10\)
=y(x-5)+2(x-5)
=(x-5)(y+2)
3: \(5x^3-20x=5x\left(x^2-4\right)=5x\left(x-2\right)\left(x+2\right)\)
4: \(x^3-3x^2-3x+1\)
\(=\left(x+1\right)\left(x^2-x+1\right)-3x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-4x+1\right)\)