If the value of x-y is negative, and x and y are both positive.
x and y are positive numbers. To get negative number while subtracting , the value of x should be less than the value of y.
For example, 5 - 9 = -4
x is 5 and y is 9 both are positive. 5 - 9 is -4 that is negative.
5 is less than 9
From this we can conclude that the value of x is less than the value of y.