Answer:

Step-by-step explanation:
<u>Exponential Growth
</u>
The natural growth of some magnitudes can be modeled by the equation:

Where P is the actual amount of the magnitude, Po is its initial amount, r is the growth rate and t is the time.
The initial number of bacteria is Po=40 and it doubles (P=2Po) at t=20 min. With that point we can find the value of r:

Simplifying:

Solving for 1+r:
![1+r=\sqrt[20]{2}](https://tex.z-dn.net/?f=1%2Br%3D%5Csqrt%5B20%5D%7B2%7D)

The exponential function that models the situation is:

$8.70 is the total cost without the coupons. He gets 6 gallons. He gets $0.55 off per gallon.
To find the total price Zak got off, multiply 6 and $0.55. 6 x $0.55 = $3.30, so he got $3.30 off.
To find the total price. Add the total cost without the coupons + the amount the coupons saved him.
$8.70 + $3.30 = $12
To find the price per one gallon, divide the total price / number of gallons
$12/6 = $2. The regular price is $2 a gallon
Answer:
180
Step-by-step explanation:
From the graph shown it can be seen that the bridge is represented by a parabola with vertex of (5, 8) and roots of 1 and 9.
Recall that the vertex form of the equation of a parabola with vertex (h, k) is given by

Thus, the equation of the given graph in vertex form is given by

Also, recall that the equation of a parabola with roots, p and q, is given by

Thus the equation of the given graph can be given by

To get the value of a, we equate both equations and solve as follows:

Therefore, the <span>function that Lindsay used to create her design is

</span>