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Sedbober [7]
2 years ago
12

The sum of the first 21 terms of the progression, - 18, - 15,-12.....is?​

Mathematics
1 answer:
katovenus [111]2 years ago
8 0
You can just use the tn formula to solve this tn= t1 + (n-1)d
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What is the difference? startfraction 2 x 5 over x squared minus 3 x endfraction minus startfraction 3 x 5 over x cubed minus 9
weeeeeb [17]

The difference of the expression \frac{2x^5}{x^2 - 3x} - \frac{3x^5}{x^3 - 9x} is \frac{2x^5(x + 3) - 3x^5}{x(x - 3)(x + 3)}

<h3>How to determine the difference?</h3>

The expression is given as:

\frac{2x^5}{x^2 - 3x} - \frac{3x^5}{x^3 - 9x}

Factor the denominators of the expressions:

\frac{2x^5}{x(x - 3)} - \frac{3x^5}{x(x^2 - 9)}

Apply the difference of two squares to x² - 9

\frac{2x^5}{x(x - 3)} - \frac{3x^5}{x(x - 3)(x + 3)}

Take LCM

\frac{2x^5(x + 3) - 3x^5}{x(x - 3)(x + 3)}

Hence, the difference of the expression \frac{2x^5}{x^2 - 3x} - \frac{3x^5}{x^3 - 9x} is \frac{2x^5(x + 3) - 3x^5}{x(x - 3)(x + 3)}

Read more about expressions at:

brainly.com/question/723406

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6 0
2 years ago
*you get 16 points*PLEASE ANSWER i’m kinda failing so help
sleet_krkn [62]

Answer:

Graph 4

Step-by-step explanation:

Parallel lines have no solution  to the system of equation.  Graph 4 is a set of parallel lines, so they will never intersect.

3 0
3 years ago
Sophia has 47 jelly beans in a bag she gives away 15 jelly beans her friends? I need help againSorry​
Gnoma [55]

Answer:

The answer I think is 32

Step-by-step explanation:

47-15=32

32

47-

15

3 0
3 years ago
Read 2 more answers
Which shows the expression? I NEED HELP RIGHT NOW PLEASE!!!
Lana71 [14]

Answer:

the 3rd option

Step-by-step explanation:

I think it is tye 3rd option from the options u have

7 0
2 years ago
In microbiology, colony-forming units (CFUs) are used to measure the number of microorganisms present in a sample. To determine
zimovet [89]

Answer:

(a)  0.2650

(b)  0.0111

(c)  0.0105

(d)  0.0006

Step-by-step explanation:

Given that:

In microbiology, colony-forming units (CFUs) are used to measure the number of microorganisms present in a sample.

Suppose that the number of CFUs that appear after incubation follows a Poisson distribution with mean μ = 15.       &;

If the area of the agar plate is 75cm²;

what is the probability  of observing fewer than 4 CFUs in a 25 cm² area of the plate.

We can determine the mean number of CFUs that appear on a 25cm² area of the plate as follows;

75cm²/25cm² = 3

Since;

mean  μ = 15  

mean number of CFUs that appear on a 25cm² = 15/3 = 5 CFUs

Thus ; the probability of observing fewer than 4 CFUs in a 25 cm² area of the plate is estimated as:

= P(X < 4)

Using the EXCEL FUNCTION ( = poisson.dist(3, 5, TRUE) )

we have ;

P(X < 4) = 0.2650

b) If you were to count the total number of CFUs in 5 plates, what is the probability you would observe more than 95 CFUs?

Given that the total number of CFUs = 5 plates; then the mean number of CFUs in 5 plates =  15×5 = 75 CFUs

The probability is therefore = P( X > 95 )

= 1 - P(X ≤ 95)

= 1 - poisson.dist(95,75,TRUE) ( by using the excel function)

= 0.0111

c) Repeat the probability calculation in part (b) but now use the normal approximation.

Let assume that the mean and the variance of the poisson distribution are equal

Then;

X \sim N (\mu = 75 , \sigma^2 = 75)

We are to repeated the probability calculation in part (b) from above;

So:

P( X > 95 )

use the normal approximation

From standard normal variable table:

P(Z > 2.3094)

Using normal table

P(Z > 2.3094) = 0.0105

(d)  Find the difference between this value and your answer in part (b).

So;

the difference between the value in part c and part b is;

=  0.0111 - 0.0105

= 6*10^{-4}

= 0.0006 to four decimal places

5 0
3 years ago
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