If g(x) = 8(1/2)^x then what is g(-1)= ?

Deshawn uses 3/4 of a box of rice to cook dinner the portion he uses weighs 12 ounces right and solve an equation to find the weight of the full box of rice

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

Having a hard time understanding this question (see attachment).