By grouping the terms in x3 - x2 - xy + x + y - 1, we get
(x + 1) (x2 - y + 1)
(x - 1) (x2 + y + 1)
(x - 1) (x2 - y + 1)
(y - 1) (x2 - y2 - 1)
x3 - x2 - xy + x + y - 1
= x2 (x - 1) -y (x - 1) + (x - 1)
= (x - 1) (x2 - y + 1)
By grouping the terms in xyz - xy - z + 1, we get
By grouping the terms in x4 - 2x3 - 6x + 12, we get
By grouping the terms in a3 + 7a2 + ba + 7b - a - 7, we get