You have to complete the square. When you do this you get an equation that looks like this: (x-3)^2 + (y+4)^2 = 4. So your center is (3, -4) and your radius is 2. That looks like B to me!!!
Let s and c be the rate of the boat in still water and the rate of the current, respectively. Then: 108/s-c=3 108/s+c=2 3s-3c=108 2s+2c=108 Solve for s and c ☺☺☺☺
