#### Answer

$QR = 11$
$RN = 11$
$QN = 22$

#### Work Step by Step

The diagonals of a parallelogram bisect each other. Therefore the point R is the midpoint of $\overline{QN}$
We can find the value of $x$:
$QR = RN$
$2x+3 = x+7$
$x = 4$
We can find $QR$:
$QR = 2x+3 = (2)(4)+3 = 11$
We can find $RN$:
$RN = x+7 = 4+7 = 11$
We can find $QN$:
$QN = QR + RN = 11 + 11 = 22$