If x+y is rational, must x and y each be rational? A Yes; because the sum of rationals is rational. B No; because the sum of irrationals is always irrational. C No; because x and y could be additive inverses of each other. D Yes; because x and ... ha warn and int entional

The correct answer is C: No; because x and y could be additive inverses of each other.

Explanation:
If x and y are rational numbers, then their sum x + y is also rational. However, if x and y are irrational numbers, their sum x + y can still be rational. For example, consider the irrational numbers √2 and -√2. Their sum is 0, which is a rational number. Therefore, it is not necessary for both x and y to be rational if their sum is rational.