x is a number such that x2+3x+9=0. What is the value of x3?

Answer 1

since (x-3)(x^2+3x+9) = x^3 - 3^3
x^3 - 3^3 = 0
x^3 = 27

Answer 2

What a great way to do this question.

Did you see the round-about way I used ??
http://www.jiskha.com/display.cgi?id=1360597831

I was even thinking of using DeMoivre's theorem.

Answer 3

I was going to show an alternative direct solution, but when I saw where it was headed, I blew it off.

Can't believe you
(a) slogged through it all
(b) got it right!