Ta có:
\(2x^2-2y^2-5x+5y\)
\(=2\left(x^2-y^2\right)-5\left(x-y\right)\)
\(=2\left(x-y\right)\left(x+y\right)-5\left(x-y\right)\)
\(=\left(x-y\right)\left(2x+2y-5\right)\)
2x2 - 2y2 -5x + 5y
= 2.(x2 -y2) - 5.(x-y)
= 2.(x+y).(x-y) - 5.(x-y)
= (x-y).(2x+2y-5)