Question 374734
If {{{x=2+i}}} is a zero so is {{{x=2-i}}},
{{{f(x)=(x-4)(x-(2+i))(x-(2-i))}}}
{{{f(x)=(x-4)(x^2-4x+5)}}}
{{{highlight(f(x)=x^3-8x^2+21x-20)}}}