Question

Given that -5 is a zero of the polynomial P(x) = x³ + 3x²-12x-10, find the other zeros.

Answer 1

Below

Explanation:

If -5 is one of the roots then that means (x+5) is one of the factors

divide (x+5) into x^3 + 3x^2 -12x -10

to get x^2-2x-2 which you can easily (using Quadratic Formula) find the roots 1 + sqrt 3 and 1 -sqrt 3

('roots' and 'zeroes' are the same thing)