If f(x) = 5x, what is f^-1(x)?

Need help pls

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Acompany manufactures three types of cabinets. it makes 110 cabinets each week. in the first week, the sum of the number of type-1 cabinets and twice the number of type-2 cabinets produced was 10 more than the number of type-3 cabinets produced. the next week, the number of type-1 cabinets produced was three times more than in the first week, no type-2 cabinets were produced, and the number of type-3 cabinets produced was the same as in the previous week.

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?