Question 1067436
if 2i is a root, so is -2i
(x-2i)(x+2i)(x-2)
x^2-4i^2=(x^2+4) (x-2) are factors
x^3-2x^2+4x-8=0
We know that (-1,15) is a point
so a[(-1)-2-4-8]=15
so that a(-15)=15
a=-1
-x^3+2x^2-4x+8 is the polynomial
{{{graph(300,300,-10,10,-30,30,-x^3+2x^2-4x+8)}}}