Using an exponential function, it is found that the mass of the radioactive sample at the beginning of the 13th day of the experiment was of 169.1 mg.
<h3>What is an exponential function?</h3>
A decaying exponential function is modeled by:

In which:
- A(0) is the initial value.
- r is the decay rate, as a decimal.
At the beginning of the first day of the experiment the mass of the substance was 500 grams and mass was decreasing by 8% per day, hence A(0) = 500, r = 0.08, and the equation is given by:



At the 13th day, the mass is given by:

More can be learned about exponential functions at brainly.com/question/25537936
Solve for x in the second equation first
Answer:
40
Step-by-step explanation:
let the unknown be y (x is used as times(multiplication) )
(y-17)x-6=-138
add /-6 to both sides
y-17x-6/-6=-138/-6
y-17=23
make y independent/add 17 to both sides
y-17+17=23+17
y=40
or in an easier way
-138/-6 =23
23+17=40
simply reversing the question to get the answer
Answer:

Step-by-step explanation:
We are given that
Equation of curves


Both curves lie on S.
We have to find the equation of tangent plane at P(4,1,4).


Hence, t=0 and u then it satisfied the given point.
Substitute the values in the derivatives


The equation of tangent at point P(4,1,4) is given by




Answer:
3x-8>22
Step-by-step explanation:
3 times a number = 3x
8 less = -8
more than 22 = >22
Put them together and you get:
3x-8>22