Answer: r = 6
Step-by-step explanation: We can use slope formula to help us solve this. Slope formula states that y = mx + b, m being the slope and b is the y-intercept, or where x = 0 in the equation. We know the slope and one pair of x and y values so to find our unknown y we must first finish slope formula by finding our y-intercept or "b".
y = 4x + b
-18 = 4 (-4) + b
-18 = -16 + b
-2 = b
Now that we know our b we can plug our known x in and solve for our unknown y.
r = 4(2) - 2
r = 8 - 2
r = 6
Therefore, your missing y value is 6.