Answer:
A and D are functions
Step-by-step explanation:
A is a function because each output is going down the same amount each time, in this case, going down by 4. (the function here is y = -x + 11)
B is not a function because there isn't a constant for y.
C isn't a function either because two x's are 0 with different y values, and you can't have that in a function.
D is also a function because of the equation on the right side.
The red line of the attachment below in A's function graphed, and the lime curve represents D's function graphed.
