College Algebra & Trigonometry, 2018a

150 CHAPTER 3. EXPONENTS AND LOGARITHMS
x
y
0 150
1 133.04
2 117.99
3 104.65
We can see that after 3 hours there are approximately 104.65 micrograms of medication
in the patient’s bloodstream.
To answer part (b) graphically, we’ll graph the original function along with the
horizontal line y =60. When we find the intersection of these two graphs, we’ll
know how long it takes for there to be 60 micrograms of medication in the patient’s
bloodstream:
150
100
50
(7.636, 60)
5 10 15 20
Here, we can see that it would take about 7.6 hours (or about 7 hours 36 minutes),
for there to be 60 micrograms of medication in the patient’s bloodstream.