Determine if planes in each pair are parallel, perpendicular, or neither.

This is what I did

n1 :[4, -5, 1]

n2:[2, -9, 1]

Dot product of n1 and n2 is not zero, so it's neither?

This is what I did

n1 :[5, -6, 2]

n2:[2, -5, -20]

Dot product of n1 and n2 is zero

What does that mean, is it parallel or perpendicular?

and how do you find out if it's parallel or perpendicular

Thanks