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I am Lyosha [343]
3 years ago
10

The sum of first three terms of an arithmetic series is 21. If the sum of the first two terms is subtracted from the third term

then it would be 9. find the three terms of the series​
Mathematics
1 answer:
Ronch [10]3 years ago
5 0

Answer:

The terms are - 1, 7 and 15.

Step-by-step explanation:

Let the terms be a-d, a and a+d

ATQ, a-d+a+a+d=21, a=7. a+d-(a+(a-d))=9. d=8. The terms are - 1, 7 and 15.

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Find the estimates of x^2-x-2=3
Julli [10]

Answer:

x=\frac{1+\sqrt{21}}{2}\approx 2.79\\or\ x=\frac{1-\sqrt{21}}{2}\approx -1.79

Step-by-step explanation:

Given

Quadratic equation is

x^2-x-2=3\\x^2-x-5=0

Roots of the quadratic equation ax^2+bx+c=0 are

x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\

So, for the given equation roots are

x=\frac{1\pm\sqrt{(-1)^2-4(1)(-5)}}{2\cdot 1}\\x=\frac{1\pm\sqrt{21}}{2}\\so, x=\frac{1+\sqrt{21}}{2}\approx 2.79\\or\ x=\frac{1-\sqrt{21}}{2}\approx -1.79

5 0
3 years ago
Which equation represents a line that passes through (5’1) and has a slope of 1/2?
Svetllana [295]

Answer:

third one passes through the slope .

4 0
2 years ago
Read 2 more answers
An author receives a contract from a publisher, according to which she is to be paid a fixed sum of $20,000 plus $3.50 for each
Schach [20]

Answer:

The mean of the total payments she will receive is $79,500.

The standard deviation  of the total payments she will receive is $14,000.

Step-by-step explanation:

Given : An author receives a contract from a publisher, according to which she is to be paid a fixed sum of $20,000 plus $3.50 for each copy of her book sold. The author judges that her uncertainty about total sales of the book can be represented by a random variable with a mean of 17,000 and a standard deviation of 4,000 books.

To find : The mean and standard deviation of the total payments she will receive ?

Solution :

Let 'x' represent total sales of the book.

Let 'y' represent the payment to the author.

According to question,

The mean of the total payments she will receive is given by,

\mu_y=20,000+3.50\mu_x

Where, \mu_x=17,000

Substitute in the equation,

\mu_y=20000+3.50\times 17000

\mu_y=20000+59500

\mu_y=79500

The mean of the total payments she will receive is $79,500.

The standard deviation of the total payments she will receive is given by,

\sigma_y=|3.50|\sigma_x

Where, \sigma_x=4,000

Substitute in the equation,

\sigma_y=|3.50|\times 4000

\sigma_y=14000

The standard deviation  of the total payments she will receive is $14,000.

7 0
3 years ago
Can someone please help me on 20 and 21
Feliz [49]
For number 20 x = 4
3 0
3 years ago
Using a rule why is = to 3 x + 4 find the value of y when x is 2
Alex73 [517]
X=2 so 2+4=6 so y=6. I just gone ovee this unit aswell.
4 0
3 years ago
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