Part B: I think the relation that has the greater value when x=6 is f(x) = 7x - 15 because:
7(6) - 15 = 27 which is greater than the output of 14.
Part C: the value of x would be 3 because:
f(x) = 7x - 15
6 = 7x - 15
+ 15 +15
21 = 7x
3 = x
Sorry if any of this is wrong.
