The value (in thousands of dollars) of a certain car is given by the following function, where t is measured in years. Find a general expression for the instantaneous rate of change of V with respect to t and evaluate this expression when t= 6 years. V = 48 t + 3 The expression for the instantaneous rate of change of V with respect to t is The instantaneous rate of change of V with respect to t at t= 6 years is]- dollars year (Round to the nearest hundred dollars as needed.)