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