A student finds the slope of the line between (20,2) and (1,17). She writes 1-17/1-20 What mistake did she make?

Answer:
i would say its c
Step-by-step explanation:
i mean cause the points say (20,1) and (1,17) she mixed up the x and y value with (20,1) she put 1-20 and im guessing not 20-1 as it stands for the points on a graph