We can use point slope form to solve for this.
y - 1 = -2(x - 2)
Simplify.
y - 1 = -2x + 4
Add 1 to both sides.
y = -2x + 5
Now, we can input -3 for x and solve for y, or r in this case.
y = -2(-3) + 5
y = 6 + 5
y = 11
r = 11
This is a bit confusing, double check if you typed everything correctly.
