1)
`x² -xy = x.(x -y)`
2)
`xy +x +y +1 = x.(y +1)+y +1 = (y +1).(x +1)`
3)
`x³ -7x² +10x = x.(x² -7x +10) = x.(x -5).(x +2)`
4)
`2.(x -3) -y.(x -3) = (x -3).(2 -y)`
5)
`x² +x +y² -y -2xy`
`= (x² -2xy +y²) +x -y`
`= (x -y)² +x -y`
`= (x -y).(x -y +1)`
6)
`x² -7x +6 = x.(x -6) -(x -6) = (x -6).(x -1)`
7)
`(x -3)² -(x² -9)`
`= (x -3)² -(x -3).(x +3)`
`= (x -3).(x -3 -x -3) = -6.(x -3)`
8)
`x² -xy +x -y = x.(x -y) +x -y = (x -y).(x +1)`
9)
`x² +4x -y² +4 = (x² +4x +4) -y²`
`= (x +2)² -y² = (x +2 -y).(x +2 +y)`
10)
`2x² +3x -5 = 2x.(x -1) +5.(x -1) = (x -1).(2x +5)`
