Correct answer is y = 3x + 1
the answer on D has been cut off..
To evaluate a function at a given input, you have to substitute every occurrence of the variable with that particular value.
So, for the first function, you have

The name of the variable is obviously irrelelvant, so the same goes for the second function:

Answer:
the three numbers below are your answers. (in order)
Step-by-step explanation:

We need more detail to help with the problem.