Helppppppppppppppppp

1) `x^2 - x - y^2 - y`

`= (x^2 - y^2) - (x + y)`

`= (x - y)(x + y) - (x + y)`

`= (x + y)(x - y - 1)`

2) `x^2 - y^2 + x - y`

`= (x^2 - y^2) + (x - y)`

`= (x - y)(x + y) + (x - y)`

`= (x - y)(x + y + 1)`

3) `3x - 3y + x^2 - y^2`

`= 3(x - y) + (x - y)(x + y)`

`= (x - y)(3 + x + y)`

4) `5x - 5y + x^2 - y^2`

`= 5(x - y) + (x^2 - y^2)`

`= 5(x - y) + (x - y)(x + y)`

`= (x - y)(5 + x + y)`

5) `x^2 - 5x - y^2 - 5y`

`= (x^2 - y^2) - (5x + 5y)`

`= (x - y)(x + y) - 5(x + y)`

`= (x + y)(x - y - 5)`

6) `x^2 - y^2 + 2x - 2y`

`= (x^2 - y^2) + (2x - 2y)`

`= (x - y)(x + y) + 2(x - y)`

`= (x - y)(x + y + 2)`

7) `x^2 - 4y^2 + x + 2y`

`= (x^2 - (2y)^2) + (x + 2y)`

`= (x - 2y)(x + 2y) + (x + 2y)`

`= (x + 2y)(x - 2y + 1)`

8) `x^2 - y^2 - 2x - 2y`

`= (x^2 - y^2) - (2x + 2y)`

`= (x - y)(x + y) - 2(x + y)`

`= (x + y)(x - y - 2)`

9) `x^2 - 4y^2 + 2x + 4y`

`= (x^2 - (2y)^2) + (2x + 4y)`

`= (x - 2y)(x + 2y) + 2(x + 2y)`

`= (x + 2y)(x - 2y + 2)`

10) `x(x - y) + x^2 - y^2`

`= x(x - y) + (x - y)(x + y)`

`= (x - y)(x + x + y)`

`= (x - y)(2x + y)`

11) `x^2 - y^2 + 10x - 10y`

`= (x^2 - y^2) + (10x - 10y)`

`= (x - y)(x + y) + 10(x - y)`

`= (x - y)(x + y + 10)`

12) `x^2 - y^2 + 20x + 20y`

`= (x^2 - y^2) + (20x + 20y)`

`= (x - y)(x + y) + 20(x + y)`

`= (x + y)(x - y + 20)`

13) `4x^2 - 9y^2 - 4x - 6y`

`= ((2x)^2 - (3y)^2) - (4x + 6y)`

`= (2x - 3y)(2x + 3y) - 2(2x + 3y)`

`= (2x + 3y)(2x - 3y - 2)`

14) `x^3 - y^3 + 7x^2 - 7y^2`

`= (x^3 - y^3) + (7x^2 - 7y^2)`

`= (x - y)(x^2 + xy + y^2) + 7(x^2 - y^2)`

`= (x - y)(x^2 + xy + y^2) + 7(x - y)(x + y)`

`= (x - y)(x^2 + xy + y^2 + 7x + 7y)`

15) `x^3 + 4x - (y^3 + 4y)`

`= x^3 + 4x - y^3 - 4y`

`= (x^3 - y^3) + (4x - 4y)`
`= (x - y)(x^2 + xy + y^2) + 4(x - y)`

`= (x - y)(x^2 + xy + y^2 + 4)`

16) `x^3 + y^3 + 2x + 2y`

`= (x^3 + y^3) + (2x + 2y)`

`= (x + y)(x^2 - xy + y^2) + 2(x + y)`

`= (x + y)(x^2 - xy + y^2 + 2)`

17) `x^3 - y^3 - 2x^2y + 2xy^2`

`= (x^3 - y^3) - (2x^2y - 2xy^2)`

`= (x - y)(x^2 + xy + y^2) - 2xy(x - y)`

`= (x - y)(x^2 + xy + y^2 - 2xy)`

`= (x - y)(x^2 - xy + y^2)`

18) `x^3 - 4x^2 + 4x - xy^2`

`= x(x^2 - 4x + 4 - y^2)`

`= x[(x^2 - 4x + 4) - y^2]`

`= x[(x - 2)^2 - y^2]`

`= x(x - 2 - y)(x - 2 + y)`