Answer:
r = 4
Explanation:
The general form of the equation is y=mx + b where m is the slope and b is the intercept. The problem tells us that the slope is -3. So we know that y=-3x+b
Let's use the known coordinate (-5,13) to solve for b.
y=-3x+b
13 = -3(-5) + b
13 = 15 + b
b = -2
So now we have the equation:
y=-3x-2
Let's use the other coordinate (-2,r) and solve for the unknown "r" (which is y):
y = -3*-2 - 2
y = 6 - 2
y = 4
So the answer is 4.