The other endpoint would have to be (-5,2), going off the definition of a midpoint. Since 3 is for units to the right of -1, that would mean that the other end point would have to be 4 units to the left, which is -5.
The temperature changed a total of 14° over the course of 7 hours with an average change of 2° per hour drop.
The width and height of the tv as well as the length and width of the back of your car

This is because 
And 
For this reason, 
Positive indices mean we have to multiply the same number twice or thrice based on the value of the index. On the other hand, negative indices mean we have to divide by the same number twice or thrice based on the value of the index.