Which equation expresses the additive inverse property?

• A. a + a = 2a
• B. a + (-a) = 0
• C. a * (-a) = -a^2
• D. a - a = 0

Answer: (B)

The additive inverse of a number is its opposite, and adding them gives zero. So the equation a + (-a) = 0 shows exactly that cancellation to zero, which is the standard way to express the additive inverse property: every number has an opposite that sums to zero.

The other forms don’t capture this idea directly: doubling a number, or multiplying by a negative, isn’t about adding an opposite to get zero; and while subtracting a from itself also yields zero, the explicit statement of the property is the sum with its opposite equal to zero.