Question

Which describes the number and type of roots of the equation x^3 + 121x = 0?

a. 2 real roots, 1 imaginary root
b. 1 real root, 2 imaginary roots
c. 3 real roots
d. 3 imaginary roots

Answer 1

b; 1 real root and 2 imaginary roots

Explanation:

From here, we have

x(x^2 + 121) = 0

x = 0 (1 real root)

or

x^2 + 121 = 0

x^2 = -121

x = √(-121) (2 imaginary roots)

so is would be two complex numbers from above