Question

Use the given zero to find all the zeros of the function.
f(x)= x3+x2+9x+9 zero= r= 3i

Answer 1

SInce all the coeffiecents are real, -3i, the complex conjugate is also a root.

Answer 2

Now use the fact that the sum of roots of an expression like

ax^3+bx^2+cx+d is (-b/a)

Let z be the unknown root.

so (3i +(-3i) + z) = -1/1

Answer 3

z=-1.

Answer 4

+-3i and -1 are the roots.

It is a cubic equation so we are looking for three roots, we have three, so it's done.