SOLUTION: The amount of medicine in​ micrograms, A, in a​ person's bloodstream t minutes after a certain quantity of it has been inhaled can be approximated by the equation Upper A= -38t

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: The amount of medicine in​ micrograms, A, in a​ person's bloodstream t minutes after a certain quantity of it has been inhaled can be approximated by the equation Upper A= -38t      Log On


   

Question 1142704: The amount of medicine in​ micrograms, A, in a​ person's bloodstream t minutes after a certain quantity of it has been inhaled can be approximated by the equation Upper A= -38tsquared +152t. How long after inhalation will there be about 114 micrograms of medicine in the​ bloodstream?
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
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-38t%5E2+%2B+152t = 114.


38t%5E2+-+152t+%2B+114 = 0.


Simplify


t%5E2+-+4t+%2B+3 = 0.


Factor left side


(t-3)*(t-1) = 0.


There are two solutions:  t= 1 minute  and  t= 3 minutes.