I need help with this question...

Plzzzz i beg u asap ! what is the equation of this graphed line? enter your answer in slope-intercept form in the box.

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

Becca wants to mix fruit juice and soda to make a punch. she can buy fruit juice for $3 a gallon and soda for $4 a gallon. if she wants to make 28 gallons of punch at a cost of $3.25 a gallon, how many gallons of fruit juice and how many gallons of soda should she buy?