#### Answer

neither

#### Work Step by Step

RECALL:
(1) Parallel lines have equal slopes.
(2) Perpendicular lines have slopes whose product is $-1$.
(3) The slope-intercept form of a line's equation is $y=mx+b$ where $m$ = slope.
Write both equations in slope-intercept form to obtain:
$\bf\text{Equation 1}:$
$7x-3y=2
\\-3y=-7x+2
\\\dfrac{-3y}{-3} = \dfrac{-7x+2}{-3}
\\y = \dfrac{7}{3}x - \dfrac{2}{3}$
$\bf\text{Equation 2}:$
$9y+21x=1
\\9y=-21x+1
\\\dfrac{9y}{9} = \dfrac{-21x+1}{9}
\\y=-\dfrac{21}{9}x+\dfrac{1}{9}
\\y=-\dfrac{7}{3}x+\dfrac{1}{9}$
The two lines have slopes that are neither equal nor negative reciprocals of each other.
Thus, the two lines are neither parallel nor perpendicular to each other.