What is a over b = -2

A / b = -2

Take note:

to have a quotient with at negative sign, both a & b must have opposites signs. a can be a positive number while b is a negative number or vice versa. If both a and b have the same sign, its quotient will be a positive number.

Let us disregard the sign.
To arrive at the answer of 2, a must be twice the amount of b. meaning a = 2b.

For example: look for a if b is equal to 2.    a = 2(2) ; a = 4.
a / b = 2
4 / 2 = 2
2 = 2

Now, we consider the sign of both numbers. a can be 4 while b can be -2  OR vice versa.

a / b = -2
4 / -2 = -2    or    -4 / 2 = -2