Answer:
A)
The product of these slopes is -1
Explanation:
The slope of perpendicular lines are negative reciprocal.This means that when you multiply the two slopes you get -1.
To find slope of a line you apply;
m=change is y-axis values/change in x-axis values
Given that there are two lines, PQ and P'Q' then to find slope you follow;
Line PQ where P(a,b) and Q (c,d) slope,m= (d-b / c-a )
Line P'Q' where P'(-b,a) and Q'(-d,c) slope , m= ( c-a / -d+b)
Multiplying the two slopes