GRAPH for math ( Ignore the answer I pressed it's obviously wrong)

Tom is making a punch that contains 80% cranberry juice and the rest ginger ale. the punch has 2 liters of ginger ale. part a: write an equation using one variable that can be used to find the total number of liters of cranberry juice and ginger ale in the punch. define the variable used in the equation and solve the equation. hint: 0.8x represents the number of liters of cranberry juice in the punch. (5 points) part b: how many liters of cranberry juice are present in the punch? show your work.

Which equation matches the graph shown ?

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=