Answer:
Perpendicular
Step-by-step explanation:
Given points P=(2,6) and Q=(4,5)
The line RS is y=2x-3.
Now we know that the line joining any two points (x1,y1) and (x2,y2) has slope m=
Now the slope of the line PQ is
m1=
= -
We know that the slope of the line in the form y=mx+c is m
So the line RS has slope m2=2
Now two lines are parallel if m1=m2
And those two lines are perpendicular if 
here m1= -
and m2=2
clearly 
Therefore the two given lines are perpendicular