Answer: C) perpendicular
Step-by-step explanation:
Each equation given to you is in y = mx+b form (aka slope intercept form).
The slope m is what we'll focus on.
The first equation has slope of 1, while the second equation has slope -1.
The two slopes multiply to -1. This is a property of any pair of perpendicular lines, as long as neither line is vertical nor horizontal.
Or you could note that -1 is the negative reciprocal of 1, or vice versa.
So there are a few options to see why the lines are perpendicular.