Solve the following problem

Drugs and Dinero When given a medication, patients often have to wait quite a while before it starts to take effect. Suppose the concentration c (in milligrams per milliliter) of a drug in a patient's bloodstream can be modeled by the function Concentration (mg/ml) c(t) = -0.000276t3 + 0.03t2 +0.44t , 20 where t represents time in minutes since the drug's injection. 20 100 Time (in minutes) 1) On a domain of [0, 140], sketch the graph of the function in the space provided. 2) What is the drug's maximum concentration in the bloodstream, and after how many minutes does the maximum occur? 3) The drug is effective when its concentration is at or above 70 mg/ml. For what length of time is the concentration at or above this level? 4) On the given domain, the function has only one maximum. Why do you think a cubic function is used to model the relationship instead of a quadratic function? Why must the domain of the function be restricted in the problem situation