Answer
Neither parallel nor 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:
$2x+5y=-8$
$5y=-2x-8$
$y=-2/5x-8/5$
And:
$6+2x=5y$
$5y=2x+6$
$y=2/5x+6/5$
The two slopes ($2/5$ and $-2/5$) are not the same and not negative reciprocals. Thus the lines are neither parallel nor perpendicular.