If i understood the question right, you're trying to find the value when h = -2. If that's true so here is how it's done:

The constant of proportionality should be 45 miles per hour, and the car should travel 135 miles in three hours.
X - y = 5,
x = 5 + y
substitute (x = 5 + y) into the first equation,
5 + y + 2y = -1
3y = -6
y = -2,
substitute y = -2 into (x - y = 5),
x + 2 = 5
x = 3
Hence, x = 3, y = -2
Answer: You have to get rid of the variables (the x's) so subtract 2x from 2x and 11x then go from there.
Step-by-step explanation: