Answer:
The slope of line r is
Step-by-step explanation:
Given as :
The points that line p contains is A ( - 1 , 4 ) and B ( 3 , - 5 )
Let The slope of line p = 
So,
= 
Or ,
= 
Or,
= 
<u />
<u>Now, Again ,</u>
Line q is parallel to the line p
let The slope of line q = 
So, for parallel lines
slope of lines are equal
I.e
= 
∴
= 
<u>Again , </u>
Line r is perpendicular to the line q
let The slope of line r = 
So, for perpendicular lines
The product of the slopes of two line = - 1
×
= - 1
or,
×
= - 1
or,
= 
∴
=
So, The slope of line r =
=
Hence , The slope of line r is
. Answer