Question

) Which replacement for a makes this not a function?

Answer 1

Here, f(x) is a function if corresponding to every image there exist a unique pre-image.

So, f(x) is not a function if a an x value repeats.

Here, the other x values are 4, 9, 12.

If the 'a' is any of these x value f(x) is not a function.

Therefore, for f(x) to be not a function 'a' should be chosen as 4.

Hence, the correct option is first option.