The given equations are-

These equations represent straight lines, where the coefficients of x are the slope of each one.
When two lines are parallel, they have the same slope, which is not the case here because the first one has a slope of 3, and the second one has a slope of -1.
Additionally, if two lines are perpendicular, their slopes are totally opposite in number and sign, which is not the case here because 3 is not opposite to -1.
Therefore, the answer is neig