Finding inputs and outputs of a two-step function that models a. Espa David wants to save $800 to buy a TV. He saves $19 each week. The amount, A (in dollars), that he still needs after is' weeks is given by the following function. A (w) -800-19w Answer the following questions. (a) If David still needs $477, how many weeks has he been saving? [weeks (b) How much money does David still need after 6 weeks? X