before we can dtermone whether it is a function, there must be a relationship between X and y i.e they must have a constannt of proportionality as shown:
From the table:
when x = 9, y = 1
when x = 7, y = 2
when x = 5, y = 2
when x = 3, y = 3
when x = 1, y = 4
let us determine the constant of proportionality from the given values as shown:
k = y2-y1/x2-x1
when x = 9, y = 1
when x = 7, y = 2
k = 2-1/7-9
k = 1/-2
k = -1/2
Also
when x = 5, y = 2
when x = 3, y = 3
k = 3-2/3-5
k = 1/-2
k = -1/2
Also;
when x = 5, y = 2
when x = 3, y = 3
k = 3-2/3-5
k = 1/-2
k = -1/2
Since all the constant of proportionality are the same;
Hence y = kx
y = -1/2 x
This shows that the tabke is a function and X is directly proportional to y. hence the answer is YES, it is function