Answer:
r = -6
Step-by-step explanation:
Use the slope formula and solve for r.
slope = y2 -y1
x2 -x1
Since you know all the numbers except for r, plug everything in and you get:
5 = 9 - r
9 - 6
So then do the arithmetic, you find that 9 - r = 15. So r must = -6.
