(i) x2 – 4 = (x + 2)(x – 2)
x2 + 4x + 4 = (x + 2)2
H.C.F. of coefficient = 1
H.C.F. of other factors = (x + 2)1 = x + 2
H.C.F. = x + 2
(ii) 4x4 – 16x3 + 12x2 = 4x2(x2 – 4x + 3)
= 4x2(x – 1)(x – 3)
6x3 + 6x2 – 72x = 6x(x2 + x – 12)
= 6x(x + 4)(x – 3)
= 2x(x – 3) [because H.C.F. of coefficients is 2]
= 2x2 – 6x