The answer should be the 1st one.
Just use the quadratic formula and plug in the necessary numbers when requested and work from there.
Answer:

Step-by-step explanation:
In order to write the series using the summation notation, first we need to find the nth term of the sequence formed. The sequence generated by the series is an arithmetic sequence as shown;
4, 8, 12, 16, 20...80
The nth term of an arithmetic sequence is expressed as Tn = a +(n-1)d
a is the first term = 4
d is the common difference = 21-8 = 8-4 = 4
n is the number of terms
On substituting, Tn = 4+(n-1)4
Tn = 4+4n-4
Tn = 4n
The nth term of the series is 4n.
Since the last term is 80, L = 4n
80 = 4n
n = 80/4
n = 20
This shows that the total number of terms in the sequence is 20
According to the series given 4 + 8 + 12 + 16 + 20+ . . . + 80
, we are to take the sum of the first 20terms of the sequence. Using summation notation;
4 + 8 + 12 + 16 + 20+ . . . + 80 = 
Hi.
The answer is:
<em />b. c(x) = 2.00 + 0.50<em>x</em>
Cheers~
The solution of the given logarithmic equation is x = 28.1
<h3>
How to solve the logarithmic equation?</h3>
Here we have the logarithmic equation:
4*ln(x - 8) = 12
And we want to solve this for x.
Remember the relations:

First, we divide both sides by 4:

Then, if we apply the exponential equation to both sides of our equation, we get:

If you want to learn more about logarithmic equations:
brainly.com/question/236421
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