Rotational symmetry of a 9 sided nonagon with Symmetry of 200

Can any one me with the answers to these questions asap?

Cherie works in retail and her weekly salary includes commission for the amount she sells. the equation s=400+0.15c models the relation between her weekly salary, s, in dollars and the amount of her sales, c, in dollars. interpret the slope of the equation.

F(x) = 2x + 1? h(x) = x – h(x) = x + h(x) = x – 2 h(x) = x + 2