Question

HELP PLEASE!

Answer 1

@mathmate

Answer 2

We have been given only one point on f(x), but we do not know anything about the function itself.
We know that (5,-8) is on the curve, so f(5)=-8.
All we know about f(x+2) is that g(x)=f(x+2) is a translation of f(x) to the left by 2 units.
Hence we know that g(3)=-8, since g(3)=f(3+2)=f(5)=-8.

To know more, we need the definition of f(x).