How do i do it it's to difficult for me

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

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5

You and a friend went to the movies.you spent half your money on tickets. then you spent 1/4 of the money on popcorn, $2 on candy, and $3 on a soda. if you have $1 left, hiw much money did u take to the movies?