9. Suppose $a, b, c$ are real numbers such that $a+b+c=0$ and $a b c=-100$. Let $x=\frac{1}{a}+\frac{1}{b}+\frac{1}{c}$. Which of the following statements is true?
(A) $x>0$
(B) $x=0$
(C) $-1<x<0$
(D) $-100<x<-1$
(E) $x<-100$
9. Ans: A
Observe that
$$
0=(a+b+c)^{2}=a^{2}+b^{2}+c^{2}+2(a b+b c+c a) .
$$

Since $a b c=-100$, it follows that $a \neq 0, b \neq 0$ and $c \neq 0$. Thus, $a^{2}+b^{2}+c^{2}>0$, and it follows that $a b+b c+c a0 .
$$