Is my answer correct?
Write an exponential function to model this situation: a population of 420 animals decreases at an annual rate of 21%. Then predict the value of the function after 5 years (to the nearest whole number).

Respuesta :

Here is the answer to the given problem above. 
Here is the exponential function to model this situation:
f(x) = 420(0.79)x
Now, solve with the given values.
P(t)=420×(.79)^t P(5)=420×(.79)^5=129
So the answer would be 129 animals.
Hope this answer helps. Thanks for posting your question!

Answer:

[tex]y=420\cdot (0.79)^x[/tex]

The value of the function after 5 years would be 129.

Step-by-step explanation:

We have been that a population of 420 animals decreases at an annual rate of 21%. We are asked to write an exponential function for our given problem.

We know that an exponential function is in form [tex]y=a\cdot b^x[/tex], where,

a = Initial value,

b = For decay b is in form [tex]1-r[/tex], where, r represents decay rate in decimal form.

[tex]r=21\%=\frac{21}{100}=0.21[/tex]

[tex]y=a\cdot (1-r)^x[/tex]

[tex]y=420\cdot (1-0.21)^x[/tex]

[tex]y=420\cdot (0.79)^x[/tex]

Therefore, our required function would be [tex]y=420\cdot (0.79)^x[/tex].

To find the value of the function after 5 years, we will substitute [tex]x=5[/tex] in our function.

[tex]y=420\cdot (0.79)^5[/tex]

[tex]y=420\cdot 0.3077056399[/tex]

[tex]y=129.236368758[/tex]

[tex]y\approx 129[/tex]

Therefore, the value of the function after 5 years would be 129.