Example 4. Given that $a, b, c$ satisfy $a+b+c=0, abc=8$. Then the range of values for $c$ is $\qquad$
(1st Hope Cup Junior High School Mathematics Invitational Competition)
Given that $a, b, c$ must be one positive and two negative. If $c$ is negative, we have $c<0$. Solving this inequality, we get $c \geqslant 2 \sqrt[3]{4}$.
Thus, the range of $c$ is
$$
c<0 \text { or } c \geqslant 2 \sqrt[3]{4} \text {. }
$$