Can someone give me an example on how to do number 18. you !

r=5

Step-by-step explanation:

The gradient(m) can be found using (y2-y1)/(x2-x1)

if we make the substitution given the points in the question, we find

(r--4)/(-5--3)

this simplifies to

(r+4)/-2

since we know that m= -9/2, we can make an equation

(r+4)/-2=-9/2

multiply both sides of the equation by -2

r+4=9

r=5