$2 \cdot 98$ The roots of the equation $|x|^{2}+|x|-6=0$
(A) are unique.
(B) sum to 1.
(C) sum to 0.
(D) have a product of 4.
(E) have a product of -6.
(9th American High School Mathematics Examination, 1958)
[Solution] The equation can be transformed into $(|x|-2)(|x|+3)=0$. Since $|x| \geqslant 0$, thus $|x|+3>0$.
From $|x|-2=0$, we get $x= \pm 2$. Therefore, the answer is $(C)$.