# The H.C.F. of x^3 + 1 and x^4 – 1 is :

A. x³ – 1

B. x³ + 1

C. x + 1

D. x – 1

**Answer: (c) x + 1 **

**Solution:-**

The factors of (X^3 + 1) = (X + 1) (X^2 + 1^2 + 2 X)

The factors of (X^4 – 1) = (X^2 – 1) (X^2 + 1)

= (X + 1) (X – 1) (X^2 + 1)

Then, the H. C. F. of X^3 + 1 and X^4 – 1 = X + 1

Hence, the correct answer is option (c) X + 1.