If the number of positive signs is even and the number of negative signs is odd then it is negative and vice versa. If the number of positive signs is even and the number of negative signs is even then the answer is odd. If the number of positive and negative signs are odd then the answer is always negative.
2/3 in simplest form is 2/3.
Let a = x^2 and b=y^2
a-b=7
4a+b=73
4(7+b)+b=73 5b=45 b=9
a=7+b = 7+9 = 16
Then
x^2=16, x=+-4
y^2=9, y=+-3
This is number 8. the second person got number 9
