Choice Bhoice D is the correct answer. To isolate the variable from an addition equation, we subtract.

1. Start with the equation: $x + 29 = 75$
2. Subtract 29 from both sides: $x = 75 - 29$
3. Calculate: $x = 46$
4. Verify: $46 + 29 = 75$ ✓

This reinforces the fundamental principle: subtraction is the inverse of addition.

Choice Bhoice D is incorrect because this results from adding instead of subtracting: $75 + 29 = 104$. We need to undo the addition, not add more.

Choice Bhoice C is incorrect because this confuses the constant term (29) with the solution. The number being added is not necessarily the answer we're looking for.

Choice Bhoice A is incorrect because this results from dividing: $\frac{75}{29} \approx 2.59$. Division is not the appropriate inverse operation for addition.