To complete this equation, it is vital to know the slope. To find the slope using points, you subtract the first x from the second, and the first y from the second. This gives you a slope of 4. Then, you must follow point-slope form and choose one of the order pairs to use. You then write y then the negative of your number. Since the number is already negative, you turn it into a positive. On the other side of the "=" sign, you write your slope, 4 distributing to x. Then you write the negative of your x value. Since it is already negative, it turns into a positive. This gives you a final answer of y+1=4(x+2). I realize that this doesn't line up with your fill-in-the-blank answer, so I am sorry if it doesn't work.
Answer:
The working is done in the image attached.
Well, Kate and Harry together are walking 100 meters per minute. Which means it will take them 25 minutes to reach each other (I think).
If the dog is running 120 meters per minute: 120 x 25 = 3,000.
The dog will run 3,000 meters (if he runs constantly to and from the spot that Kate and and Harry started).