\(C1:x^2-2x+xy-2y\\ =x\left(x-2\right)+y\left(x-2\right)\\ =\left(x-2\right)\left(x+y\right)\\ C2:x^2-2x+xy-2y\\ =x\left(x+y\right)-2\left(x+y\right)\\ =\left(x+y\right)\left(x-2\right)\)
Cách 1:
\(x^2-2x+xy-2y\)
\(=\left(x^2-2x\right)+\left(xy-2y\right)\)
\(=x\left(x-2\right)+y\left(x-2\right)\)
\(=\left(x+y\right)\left(x-2\right)\)
Cách 2:
\(x^2-2x+xy-2y\)
=\(\left(x^2+xy\right)+\left(-2x-2y\right)\)
\(=x\left(x+y\right)-2\left(x+y\right)\)
=\(\left(x-2\right)\left(x+y\right)\)
x2 - 2x + xy - 2y=x(x-2) + y(x - 2)=(x + y) (x - 2)