For the statement that says:

b + (-a) = b - a

What property would that be? Is it the addition property of equality? or something else.

Adding a negative number is the same as subtracting a positive number.

a + (-b) = a - b.

To determine the property being demonstrated by the equation b + (-a) = b - a, we need to understand the properties of equality in mathematics.

The property being used here is called the additive inverse property. According to this property, for any number a, its additive inverse, denoted as -a, is the number such that a + (-a) = 0.

In the given equation, b + (-a) = b - a, we can see that the -a term acts as the additive inverse of a. By subtracting a, we are essentially adding its additive inverse (-a) to b.

Therefore, the property being demonstrated here is the additive inverse property, not the addition property of equality.