The line that is the perpendicular bisector of the segment whose endpoints are r(-1, 6) and s(5, 5)

I think what you are looking for is to indicate an ecuation for this. So lets do the procedure: 
First you need to find the slope of this line. 
(5 - 6)/(5 + 1) = -1/6 
So, The slope of the perpendicular line is the opposite reciprocal, which is 
+6/1.Now we know the slope of the line but still have to find the mid point of the line. 
That is why we are going to use the mid point equation 
x = (-1 + 5)/2 = 2 
y = (6 + 5)/2 = 11/2  
(y - 11/2) = 6(x - 2) 
The last thing you do is rearrange the equation to get y = 6x - 6.5
Hope this is what you were looking for