Question

Which of the following polynomials does not have real roots?

A. x2 - 17x - 7
B. -x4 + 4x2 + 6
C. x4 + 2x2 + 2
D. 2x2 - 13 ...?

Answer 1

C.

Explanation:

x4 + 2x2 + 2 has no real roots

Answer 2

the answer is x4 + 2x2 + 2,
proof
if a is a (real) is a root of x4 + 2x2 + 2, so
a4 +a2 +2 =0, it is impossible, because a4>0, a2>0 and 2>0
a4 +a2 +2 must be >0, so x4 + 2x2 + 2 doesnt have real roots