Answer:
-10.2n - 1
Step-by-step explanation:
We have two expressions in variable n and we have to add the two expressions.
An important thing to note is that only like terms can be added. i.e. the term with "n" can only be added or subtracted to the term with "n". Similarly a constant can only be added or subtracted to a constant.
Thus, the two given expressions add up to -10.2n - 1
Answer:
about 81 years
Step-by-step explanation:
A graphing calculator can give you the answer easily.
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You can solve the problem algebraically by putting in the given number and solving for t.
30000 = 32000/(1 +12.8e^(-.065t))
12.8e^(-.065t) = (32000/30000) -1 = 1/15
e^(-.065t) = 1/(15·12.8) = 1/192 . . . . . divide by 12.8
-0.065t = ln(1/192) ≈ -5.257 . . . . . . take the natural log
t = -5.257/-0.065 ≈ 80.88 . . . . . . . .divide by the coefficient of t
It will take about 81 years for the number of trees to reach 30,000.
