Eight times eight equals sixty four
Answer: The inverse relation is { (-1, -8), (-1, -8), (-8, -2), (8, 2) }
The inverse is effectively the opposite of the original relation. It undoes what the original relation does. So we'll swap the x and y values for each given point in the form (x,y). Something like (8,-1) becomes (-1,8). The other points follow the same pattern as well.
In order for two linear lines to be perpendicular, the product of their gradient must be -1.
Let's take y = x + b and y = -x + b
This is already in the form: y = mx + b, where m is 1 and -1 respectively.
Since the product of their gradient is -1, they are said to be perpendicular.