Question 1113706
The roots are 4, -14, and if 5+8i is a root, so is 5-8i
(x-4)(x+14)(x-5-8i)(x-5+8i) are all the roots.
(x^2+10x-56)(x^2-10x+25+64) which is what -64i^2 is.
(x^2+10x-56)(x^2-10x+89)
=x^4-67x^2+1450x-4984
{{{graph(300,300,-20,10,-1000,1000,x^4-67x^2+1450x-4984)}}}