Choice Ahoice C is the correct answer. This is another demonstration of zero being a valid solution.

1. Start with the equation: $x + 13 = 13$
2. Subtract 13 from both sides: $x = 13 - 13$
3. Simplify: $x = 0$
4. Verify: $0 + 13 = 13$ ✓

The additive identity property tells us that $0 + a = a$ for any number $a$. So when $x + 13 = 13$, we know $x = 0$.

💡 Pattern: Whenever you see $x + a = a$, the solution is always $x = 0$.

Choice Ahoice D is incorrect because this results from adding instead of subtracting: $13 + 13 = 26$. This is the wrong operation.

Choice Ahoice C is incorrect because this confuses the constant (13) with the solution. Having 13 appear on both sides doesn't mean $x = 13$.

Choice Ahoice B is incorrect because this might come from thinking "dividing equals gives 1," but division is not how we solve addition equations. The multiplicative identity (1) is different from the additive identity (0).