Checking statement 1 x – y = 8 Both x and y must be positive for any value of x and y. It is not true because negative values of x and y or positive x 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 alos 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, neithter 1 nor 2 nor 3