In a function, how is the x-value related to the y-value?

• A. Each x-value has exactly one corresponding y-value.
• B. Each x-value has multiple possible y-values.
• C. The y-value determines the x-value.
• D. X-values are always negative.

Answer: (A)

In a function, each input value (the x-value) is paired with exactly one output value (the y-value). This means for any x you pick from the domain, you should get a single y. If the same x could give more than one y, it wouldn’t be a function.

So the statement that each x-value has exactly one corresponding y-value is the best description. For example, in a valid function like y = x^2, choosing x = 3 gives a single y, namely 9. The idea that an x could map to multiple y’s would violate the function rule, and the notion that the y-value determines the x-value reverses the direction of the mapping. Also, x-values aren’t restricted to negative numbers; a function can have x-values from any allowed domain, including positive numbers and zero.