Answer
$d(C, E) = 3$
Work Step by Step
$d(C, E)$ represents the distance between the points C and E on a number line.
If the coordinates of C and E are $c$ and $e$, respectively, then:
$d(C, E) = |c-e|$
Based on the given number line, the coordinates of C and E are $0$ and $3$, respectively.
Use the formula above to obtain:
$d(C, E) = |0-3| = |-3| =3$
Thus,
$d(C, E) = 3$
