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soldi70 [24.7K]
3 years ago
7

If x + y = 12 and xy = -5, calculate the value of 1/x + 1/y.​

Mathematics
1 answer:
Paul [167]3 years ago
8 0

\dfrac{1}{x}+\dfrac{1}{y}=\dfrac{y}{xy}+\dfrac{x}{xy}=\dfrac{x+y}{xy}=\dfrac{12}{-5}=-\dfrac{12}{5}=-2,4

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Find the slope of the line through the given points. d (3, 7) and (3, −8)
Romashka [77]

Answer:

Undefined

Step-by-step explanation:

Use rise over run (y2 - y1) / (x2 - x1), where (x1, y1) and (y1, y2) are points on the line

Plug in the given points:

(y2 - y1) / (x2 - x1)

(-8 - 7) / (3 - 3)

-15/0

= undefined

The slope is undefined, because you cannot divide by 0.

6 0
3 years ago
Please help! this is for a test! what do i write???
Nadya [2.5K]

Answer:

128/3 - peas 128/9 corn

Step-by-step explanation:

it is too long

7 0
3 years ago
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A report includes a statement that the​ "average" test score of applicants to medical schools is 28.4. What is the role of the t
qaws [65]

Answer:

See explanation below.

Step-by-step explanation:

The average is measure of central tendency that is also called sample mean and is calculated from the following formula:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

This is an estimator of the population mean and is unbiased since the expected value for the estimator is the same parameter as we can see here:

E(\bar X)=\frac{\sum_{i=1}^n E(X_i)}{n} =\frac{n\mu}{n}=\mu

And is important because is the most common measure of central tendency reported on any study.

Is important to remember that this measure can be affected by outliers , for this case when we have outliers is better use the median as a measure of central tendency

7 0
3 years ago
Brad has eight more nickels than quarters. Altogether he has $6.10. how many of each does he have
wlad13 [49]

Brad have 19 quarters and 27 nickels.

Step-by-step explanation:

Given,

Total worth of nickels and quarters = $6.10 = 6.10*100 = 610 cents

One quarter = 25 cents

One nickel = 5 cents

Let,

x represent the number of quarters.

y represent the number of nickels.

According to given statement;

25x+5y=610     Eqn 1

y = x+8              Eqn 2

Putting value of y from Eqn 1 in Eqn 2

25x+5(x+8)=610\\25x+5x+40=610\\30x=610-40\\30x=570

Dividing both sides by 30

\frac{30x}{30}=\frac{570}{30}\\x=19

Putting x=19 in Eqn 2

y=19+8\\y=27

Brad have 19 quarters and 27 nickels.

Keywords: linear equation, subtraction

Learn more about subtraction at:

  • brainly.com/question/9369548
  • brainly.com/question/9328925

#LearnwithBrainly

7 0
2 years ago
Please look at the picture down below
Setler79 [48]

Answer:

D. 7.29.

Step-by-step explanation:

For a Normal Distribution:

Q1  = mean - (0.675) * standard deviation

= 8.5 - 0.675*1.8

= 7.285.

3 0
3 years ago
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