Answer
$_7P_2=42$
Work Step by Step
RECALL:
$_nP_r = \dfrac{n!}{(n-r)!}$
Use this definition to have:
$\require{cancel}
_7P_2=\dfrac{7!}{(7-2)!}
\\_7P_2=\dfrac{7!}{5!}
\\_7P_2 = \dfrac{7(6)(5!)}{5!}
\\_7P_2 = \dfrac{7(6)\cancel{(5!)}}{\cancel{5!}}
\\_7P_2=42$
