Answer
Let (x+p) be one of the factors.
$$(x-1)^3(x+p) = x^4+αx^3+βx^2+γx-1$$
$$x^4+x^3(p-3)+x^2(3-3p)+x(p-1)-p= x^4+αx^3+βx^2+γx-1$$
On comparing constant terms,
-p=-1
p=1
So, (x+1) is one of the factors.
Answer (A) – (x+1)
Let (x+p) be one of the factors.
$$(x-1)^3(x+p) = x^4+αx^3+βx^2+γx-1$$
$$x^4+x^3(p-3)+x^2(3-3p)+x(p-1)-p= x^4+αx^3+βx^2+γx-1$$
On comparing constant terms,
-p=-1
p=1
So, (x+1) is one of the factors.
Answer (A) – (x+1)