## Precalculus (6th Edition)

$d(Q, R)=12$
RECALL: The distance between the points Q and R on a number line, whose coordinates are q and r, respectively, is given by the formula: $d(Q, R) = |q-r| \text{ or } d(Q, R) = |r-q|$ Use the formula above, with $q = -1$ and $r=8$, to obtain: $d(P, R) \\=|8-(-4)| \\=|8+4| \\=|12| \\=12$