Question

find all real and complex zeros of the polynomial function f(x)=x^3+4x

Answer 1

The Function is f(x)  =  x^3 + 4x

To find out zeros equate the function to zero

x^3 + 4x  =  0

x(x^2 + 4)  =  0

x  =  0      ;      (x^2 + 4)  =  0

x  =  0      ;      x^2  =  -4

x  =  0      ;      x  =  ±√(-4)

x  =  0      ;      x  =  2i            ;      x  =  -2i

Answer :

The real zero is 0

The complex zeros are +2i and -2i.