Two friends, 7 miles apart, start walking toward each other, and they meet in an hour. if one boy walks 1 mile farther in an hour than the other boy, how fast does each walk?

So lets say the distance one boy travels is 'x', you can set up an equation like this:
x + x + 1 = 7
2x +1 = 7
2x = 6
x = 3
So one boy walks 3 miles in one hour, and the other walks 4 miles in one hour.
Therefore, their speeds are 3 miles per hour and 4 miles per hour respectively.

The coordinates of point a right now is (-3,-1) you have to multiply these coordinates by a factor of 2 to get (-6,-2)