9^0 its that answer because all the other number you can make a whole number.
The answer to the f(x) is D f(x) = 3x + 3 because (x,y) you input x into the equation and you get y, if that makes sens, u said u need it now so I won't go into it too much.
As

increases, [y] is expected to increase.
It's thirteen because it is too large.