Shen wants to save $800 to buy a TV. He saves $17 each week. The amount, A (in dollars), that he still needs after W weeks is given by the following function. A (w) = 800 - 17w

Answer the following questions.
(a): If Shen still needs $477, how many weeks has he been saving?
(b): How much money does Shen still need after 6 weeks?