Question

Which of these represents a quadratic polynomial with exactly two zeros given by - 21 and 2i?

A. O f(x) = x2 – 4
B. O f(x) = x2 +4
C. O f(x) = 2x2
16
D. O f(x) = 2x2 + 16

Answer 1

B

Explanation:

(x + 2i)(x - 2i)

= x² - 2ix + 2ix - (2i)²

= x² - 4i²

= x² -4(-1)

= x² + 4

Answer 2

B. x² + 4

Explanation:

(0+/-√-16)2

+/- 4i / 2

+/- 2i