If f(x)=2x+7, find the value of x when f(x)=17

If you could answer these your a life saver

If g^-1(x) is the inverse of g (x) which statement must be true

Atorch and a battery cost 2.50 altogether. the torch costs 1.50 more than the battery. what fraction of the total price is the torch? give your answer in its simplest form.