This is because ordered pairs are written in the form (x,y), where the first number represents the number of units the point has moved along the x axis and the second number represents the number of units the point has moved along the y axis. Point Z is on the y axis, which means it has moved 0 units along the x axis (it has an x value of 0). Its y value is -t because it has the same y value as the point directly above it, except it is negative (it moved down instead of up). Therefore, the answer is (0,-t).
