Question

I don't understand this :
F(9) if f(x) = x+13

Answer 1

what it basically is saying is plug in 9 for x so for example f(x)=x+13 would become f(9)=9+13 so therefore f(9)=22

Answer 2

F(X) = X + 13
F(9) = (9) + 13
F(9) = 22.