Could you help me with this problem please. Please show steps on how to compute. Thank you.

a) The spread of oil leaking in the ocean is the form of a circle. If the radius of the oil spread aftert hours isr(t)=155t, find the area of the oil spread in terms of timet. A(t)=?

b)Your local grocery store is having a 15 % off everything sale. But Wait!!!! For the next 3 days they are offering a coupon to save an additional $ 21 on any order over $100. If the store applies the sale price then applies the coupon, find each of the following.Assume the order is over $100 and letx

represent the price of any item.Round all decimals to 4 decimal places.

• What is the function calledsale(x) that will directly calculate the final price of an item.sale(x)=?
• What is the function calledelas(x) that will directly calculate the final price of an item in the discounts are applied in reverse order. elas(x)=?