Given f(x) and g(x)=k×f(x), ise the graph to determine the value of k

Is a deceasing linear model or an exponential decay model likely to be a better fit for the data about remembering? ?

Me answer number 3plz explain how you do it

You eat 8 strawberries and your friend eats 12 strawberries from a bowl. there are 20 strawberries left. which equation and solution give the original number of strawberries?