Problem: The real factors of x2+4 are:
Answer Choices:
A. (x2+2)(x2+2)
B. (x2+2)(x2−2)
C. x2(x2+4)
D. (x2−2x+2)(x2+2x+2)
E. non-existent
Solution:
It is understood that we restrict ourselves to rational coefficients and integral powers of x. With this restriction x2+4 is not factorable.