Part A: the data represent a function because for each value of x, there is a unique value of y.
Part B: from the table, when x = 7, y = 8. from the function f(x) = 2x + 13, f(7) = 2(7) + 13 = 14 + 13 = 27. Hence f(x) = 2x + 13 has a greater value when x = 7.