If I read these symbols correctly, for d:

Because the power of x is 0 (x≠0), this function becomes y= 1, which is just a constant function, not a functional relationship between y and X. 。

Answer a and c to the first question;

In fact, the value range of X in A's answer should be X > 0, because in the root number X (that is, √x/x) of X, X as the denominator cannot be equal to 0, but to make the root number X meaningful, X should be greater than or equal to 0. Therefore, x should be greater than 0.

And C, the answer X should be x≥0, because this is purely to make the radical X meaningful, so it is x≥0.

For the second question:

In fact, in D's answer, the root number x+3 is 1 (i.e.1√ x+3), and the root number X+3 (i.e. √x+3) is analyzed separately. To make it meaningful, x should be greater than or equal to -3 (that is, x≥-3), and because the root number X+3.