Find a third-degree polynomial equation with rational coefficients that has roots - 4 and 2 + i

If it has rational coefients and is a polygon

if a+bi is a root then a-bi is also a root

the roots are - 4 and 2+i

so then 2-i must also be a root

if the rots of a poly are r1 and r2 then the factors are

f (x) = (x-r1) (x-r2)

roots are - 4 and 2+i and 2-i

f (x) = (x - (-4)) (x - (2+i)) (x - (2-i))

f (x) = (x+4) (x-2-i) (x-2+i)

expand

f (x) = x³-11x+20