Answer
9
Work Step by Step
In order to find the distance between two points, we can find the absolute value of the difference of the numbers (taken in either order).
$A=-4$
$C=5$
$|(-4-5)|=|-(4+5)|=|-(9)|=|-9|$
The absolute value of a number $a$ is equal to $a$ if $a\geq0$ and is equal to $-a$ if $a\lt0$.
$-9\lt0$, so $|-9|=-(-9)=9$
Therefore, the distance between the two points is 9.