D, Each x value has one and only one y value.; This is because if an x-value repeats itself then it is not a function. You can test this on a graph by drawing a vertical line on it. If the vertical line intercepts the line more than once anywhere on the graph, then it is not a function.
Answer:
Each x value has one and only one y value.
Step-by-step explanation:
y = f(x) can be called a function if, and only if
f(a) = f(b) means that a = b.
That is, each x value has one and only one y value.
y = 4 - 6x
f(a) = f(b)
4 - 6a = 4 - 6b
6b = 6a
b = a
So the correct answer is:
Each x value has one and only one y value.
