vector line subtraction, pls explain. thanks

By looking at the vectors a - c below, figure out what subtraction problem was being performed, and then state the answer. For instance, vector d came from doing the problem -1 - 5 since the initial point of that vector is on 5 and the terminal point is on -1. Since vector d is 6 units long and goes left, it represents the number -6. Therefore, vector d would be: -1 - 5 = -6. If you are subtracting a negative number, enclose the negative number in parentheses, for example, 9 - (-2) = 11. vector d vector a vector c vector b N + T O 7 8 9 10 11 12 13 14 a. Vector a : b. Vector b : c. Vector c