Question

The table shows the outputs y for different inputs x:

Answer 1

Part A: yes, because every input value x produces only one output value y. 

Part B: in the first function, when x=7, why=8 is given
in the second function, when x=7, y=2x+13=27
so the second function has a greater value when x=7

Part C: when f(x)=2x+13=75, 2x=62, x=31