Answer:
0
Explanation:
You want to know the additive identity element.
Additive identity
The additive identity element is the number that, when added to the expression, leaves an expression with its original identity: it does not change the value.
It satisfies ...
(original expression) + (additive identity) = (original expression)
Using the subtraction property of equality, we can subtract (original expression) from both sides of this equation. That tells us ...
(additive identity) = 0
The additive identity element is zero (0). Adding zero changes nothing.
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Additional comment
In subtracting (original expression) from both sides of the above equation, we end up with the expressions on either side of the equal sign:
(original expression) - (original expression)
The "additive inverse" of an expression is its negation. The additive inverse meets the requirement that adding an expression and its additive inverse results in zero. Effectively, we bypassed the step ...
0 + (additive identity) = 0
Without worrying too much about the deep details here, we made the claim that (additive identity) = 0. In the end, that can be regarded as a matter of definition.