Question 759161
Each of the roots gives you a binomial factor which composes the function.  The simplest function for your given roots is 
{{{f(x)=(x-10)(x-(2i))(x-(-2i))}}}
Simply do the multiplications if you want general form:


{{{(x-2i)(x+2i)=x^2-(4i^2)=x^2+4}}}, taken care of only the complex roots.


{{{(x-10)(x^2+4)=x^3-10x^2+4x-40}}}, included the other root.


{{{highlight(f(x)=x^3-10x^2+4x-40)}}}