Functions graphics I need help please I don’t understand which one is a function and which one is not a function

What can be said about the relationship between triangles and circles? check all that apply. a) many circles can be inscribed in a given triangle b) exactly one triangle can be inscribed in a given circle c) exactly one circle can be inscribed in a given triangle d) many triangular shapes can be circumscribed about a given circle

Restrictions on f(x) = 1/x+5 and g(x) = x-2

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12