[tex] {x}^{4} + 8 {x}^{3} + 16 {x}^{2} - 25 = (x^2 + 4x + 5)(x^2 + 4x - 5)[/tex]
[tex] {x}^{2} + 6x - {y}^{2} + 4y + 5 = (x + 3)(x + 3) - (y - 1)(y - 5)[/tex]
[tex] (x + 3y)(x + 3y - 6) - (y + 3)(y - 3) = (x + 3y - 3)(x + 3y - 3)[/tex]
[tex]3 {x}^{2} - 4xy + {y}^{2} + 4x - 4 = (x - y + 2)(3x - y + 2)[/tex]
[tex] {x}^{4} + 8 {x}^{3} + 16 {x}^{2} - 25 = (x^2 + 4x + 5)(x^2 + 4x - 5)[/tex]
[tex] {x}^{2} + 6x - {y}^{2} + 4y + 5 = (x + 3)(x + 3) - (y - 1)(y - 5)[/tex]
[tex] (x + 3y)(x + 3y - 6) - (y + 3)(y - 3) = (x + 3y - 3)(x + 3y - 3)[/tex]
[tex]3 {x}^{2} - 4xy + {y}^{2} + 4x - 4 = (x - y + 2)(3x - y + 2)[/tex]