Question

Which of the following expressions is equal to x^2+16?

A. (x + 4i)(x-4i)
B. (x +4i)^2
C. (x-4i)^2
D. (x + 2i)(x - 8i)

Answer 1

A

Explanation:

x² + 16 = 0

x² = - 16

x² = i² * 4² {i² = -1}

x² = (4i)²

x=√(4i)²

x=±4i

x² + 16 = (x + 4i)(x - 4i)