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in order for an antibiotic to be effective 5 or more mg/dl must be present in the bloodstream. When do you have to take the antibiotic after the initial dose? Solve algebraically and graphically 

 

Equation: c(t)= 55t/t*2+25

 Oct 17, 2019
 #1
avatar+106539 
+1

   55t

_______    =      5

t^2 + 25

 

Multiply both sides by   t^2 + 25

 

55t   =  5(t^2 + 25)        divide both sides by 5

 

11t  =  t^2 +  25    rearrange as

 

t^2   - 11t +  25  =  0    

 

Using the quaratic fromula

 

11    ±√[11^2 - 4(1)(25)]

____________________

              2

 

11   ±√[121 - 100]

_______________

             2

 

11  ±√21

________

      2

 

Take the least value of  t     =       

 

 

11  -  √21

________  ≈    3.2 hrs

      2 

 

 

Heres the graph  :   https://www.desmos.com/calculator/ejgdwf1ijg

 

 

cool cool cool

 Oct 17, 2019

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