Astudent found the slope of a line that passes through the points (1, 14) and (3, 4) to be 5. what mistake did she make?

The student interchanged the calculations when finding the values of change in x and y;
The student may have started by 14-4 but started with 3-1 for change in x.

M = (y2-y1)/(x2-x1)
 = (4-14)/(3-1)
 = (-10)/(2)
 = -5
slope is -5