In the diagram below of triangle
P
Q
R
PQR,
S
S is the midpoint of
P
R
‾
PR
and
T
T is the midpoint of
Q
R
‾
QR
​
. If
S
T
=
−
22
+
9
x
ST=−22+9x, and
P
Q
=
9
x
−
8
PQ=9x−8, what is the measure of
P
Q
‾
PQ
​
?