1) the expression that gathers the expenses and the income is the utility function and is defined by U(t) = I(t)-G(t), where I(t) is income and G(t) is expenses, the simplest form that represents the total amount of the balance of the expense account is, for this exercise I(t) = 275+48t and G(t) = 450-70t
PART A
U(t)= 275+48t-(450-70t) ⇒U(t) = 275+48 t-450+70t⇒U(t) = 118t -175
PART B
For f(t) = (275+48t) the total amount (in dollars) after 9 weeks?
it is f(9) = [(450 - 70(9)]= $220
for f(t) =275 +48t ,the total amount in dollars after 9 weeks is f(9) = 275+48(9) = $ 707