Question

Find all zeros of the function

Answer 1

x=-1,-3,2i and -2i

Explanation:

By plugging in x=-1, f(x)=0 and x=-3,f(x)=0

That means x+1 and x+3 are roots of the fourth degree polynomial.

(x+1)(x+3)=x²+4x+3

Divide the polynomial by x²+4x+3 and that gives x²+4.

We now find the zeros of the factors

(x²+4x+3)(x²+4)=0

x=-1,-3,2i and -2i