Problem: The factors of the expression x2+y2 are
Answer Choices:
A. (x+y)(x−y)
B. (x+y)2
C. (x2/3+y2/3)(x4/3+y4/3)
D. (x+iy)(x−iy)
E. none of these
Solution:
x2+y2 has no linear factors in the real field. x2+y2=(x+iy)(x−iy) in the complex field.