The answer is (20,0). We can determine the sum of two vector points by adding x1 to x2 and y1 to y2. This is like adding integers, the only difference is the answer is in vector form. In here, we have (x,y). x = 7+13 and y = 5+(-5). that is why we have the (20,0) as the answer.
It’s negative slope since it’s going to the left
The value of c to complete the square is one. In order to find the c value you divide the b value (-2) by 2 (-1) and then square that. -1 squared is 1. This can then be easily factored into (x-1)^2