Solution:Checking statement 1
x − y = 8
Both x and y must be positive for any value of xxx andy.
It is not true because negative values of xxx and yyy or positive xxx and negative y is also possible.
Checking statement 2
If x is positive, y must be negative for any value of x and y.
It is also not true because positive values of x and y are also possible.
Checking statement 3
If x is negative, y must be positive for any value of x and y.
Here if x is negative then only negative value of y is possible.
Hence, neither 1 nor 2 nor 3