A slope of -2 would mean that for every 2 DOWN on the y axis, one unit is traversed on the x axis. Meaning that adding (1, -2) to any points would calculate the remaining points on such a sloped line.
(-3,5) —> (1,r)
1 is 4 away from -3
4 times -2 is -8
So r = 5-8
R=-3
