Problem

甲、填充題：共 10 題，每題 8 分，共 80 分。請將答案依題號順序寫在答案卷上，不必寫演算過程。

6. Suppose that the edge lengths $x$, $y$, and $z$ of a rectangular box are changing at the following rates: $\dfrac{dx}{dt}=1$ m/sec, $\dfrac{dy}{dt}=-2$ m/sec, $\dfrac{dz}{dt}=1$ m/sec. Find the rate at which the box’s volume is changing at instant when $x=4$, $y=3$, and $z=2$. Answer : \underline{\quad(1)\quad}