Answer
Perpendicular.
Work Step by Step
We know that two parallel lines have the same slope ($m_1=m_2$).
We also know that perpendicular lines have negative reciprocal slopes ($m_1=-\frac{1}{m_2}$).
A line in slope-intercept form has the equation:
$y=mx+b$ ($m=slope$, $b=y-intercept$)
We put the line equations into slope-intercept form:
$2x=y+3$
$y=2x-3$
And:
$2y+x=3$
$2y=-x+3$
$y=-1/2x+3/2$
The two slopes ($2=2/1$ and $-1/2$) are negative reciprocals. Thus the lines are perpendicular.