The table shows the outputs y for different inputs x: input (x) 5 6 7 8 output (y) 2 5 8 11 part a: do the data in this table represent a function? justify your answer. (3 points) part b: compare the data in the table with the relation f(x) = 2x 13. which relation has a greater value when x = 7? (2 points) part c: using the relation in part b, what is the value of x if f(x) = 75? (5 points)

Part 1.) This is indeed a function. A function means that there no x values have multiple (different) values
For example:
x   y
1   4
2   6      <-- First x
3   8
2   10    <-- Different y-val from first x (2)
5   12

Part 2.) I'm assuming the relation is actually f(x) = 2x + 13. If so, input 7 as x.
  f(7) = 27.
  27 > 8.
  Second relation has greater value when x = 7

Part 3.) Work backwards using this information
  75 = 2x + 13
  62 = 2x
  31 = x      <-- x is equal to 31

Your answer is d)magnesium