The endpoints of a side of rectangle abcd in the coordinate plane are at a (2, 11) and b (7, 1). find the equation of the line that contains the given segment. the line segment is ad. the equation is y = .

We know that
A (2, 11) and B (7, 1)

step 1
find the slope of a line AB
the slope m=(y2-y1)/(x2-x1)------> m=(1-11)/(7-2)---> m=-10/5----> m=-2

step 2
find the equation of a line AD

we know that
the segment AB and the segment AD are perpendicular
so
m1*m2=-1
m2=-1/m1-----> m2=1/2

with the slope m2=1/2 and the point A(2,11)
y-y1=m*(x-x1)------> y-11=(1/2)*(x-2)----> y=(1/2)x-1+11
y=(1/2)x+10----> y=0.5x+10

the answer is 
the equation of a line AD is y=0.5x+10

see the attached figure