Answer:

Step-by-step explanation:
Let the two numbers be x and y
So we have:

using the elimination method, add the two equations together:

solve for x:

substitute our value for x back into the first equation we made:

therefore,

Answer:

Step-by-step explanation:
Given:
To find:
- Summation notation of the given series
Summation Notation:

Where n is the number of terms and
is general term.
First, determine what kind of series it is, there are two main series that everyone should know:
A series that has common difference.
A series that has common ratio.
If you notice and keep subtracting the next term with previous term:
Two common difference, we can in fact say that the series is arithmetic one. Since we know the type of series, we have to find the number of terms.
Now that brings us to arithmetic sequence, we know that first term is 5 and last term is 251, we’ll be finding both general term and number of term using arithmetic sequence:
<u>Arithmetic Sequence</u>

Where
is the nth term,
is the first term and
is the common difference:
So for our general term:

And for number of terms, substitute
= 251 and solve for n:

Now we can convert the series to summation notation as given the formula above, substitute as we get:

Answer:
The costs of the plan are $0.15 per minute and a monthly fee of $39
Step-by-step explanation:
Let
x ----> the number of minutes used
y ----> is the total cost
step 1
Find the slope of the linear equation
The formula to calculate the slope between two points is equal to

we have the ordered pairs
(100,54) and (660, 138)
substitute


step 2
Find the equation of the line in point slope form

we have

substitute

step 3
Convert to slope intercept form
Isolate the variable y

therefore
The costs of the plan are $0.15 per minute and a monthly fee of $39
The answer is: 1.25x + 1.75
The third one because each banner costs $16 and x is the number of banners, $32 is just a one time fee so there is no x.