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2 years ago

15

you have 26 books.you return some books.then you take out 15 more books.now you have 27 books.how many books did you return? sol

ve anyway

1 answer:

Luda [366]2 years ago

8 0

Answer:

14 books were returned.

Step-by-step explanation:

You would have to first

27-15=12

26-12=14

(I hope that this helps)

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Factor 4x^4+7x^2-2=0

natulia [17]

Answer:

(2x-1)(2x+1)(x^2+2) = 0

Step-by-step explanation:

Here's a trick: Use a temporary substitution for x^2. Let p = x^2. Then 4x^4+7x^2-2=0 becomes 4p^2 + 7p - 2 = 0.

Find p using the quadratic formula: a = 4, b = 7 and c = -2. Then the discriminant is b^2-4ac, or (7)^2-4(4)(-2), or 49+32, or 81.

Then the roots are:

-7 plus or minus √81

p= --------------------------------

8

p = 2/8 = 1/4 and p = -16/8 = -2.

Recalling that p = x^2, we let p = x^2 = 1/4, finding that x = plus or minus 1/2. We cannot do quite the same thing with the factor p= -2 because the roots would be complex.

If x = 1/2 is a root, then 2x - 1 is a factor. If x = -1/2 is a root, then 2x+1 is a factor.

Let's multiply these two factors, (2x-1) and (2x+1), together, obtaining 4x^2 - 1. Let's divide this 4x^2 - 1 into 4x^4+7x^2-2=0. We get x^2+2 as quotient.

Then, 4x^4+7x^2-2=0 in factored form, is (2x-1)(2x+1)(x^2+2) = 0.

6 0

3 years ago

What is the value of the x variable in the solution to the following system of equations?

Dimas [21]

The answer is 3. I hope this helps :))

7 0

2 years ago

HELLLPPPPPPP .... The probabilities of a test are represented by I for infected; U, uninfected; D, infection detected; and N, no

Dominik [7]

Answer:

P(I⋂D)

Step-by-step explanation:

The symbolic way to represent the probability of a true positive is P(I⋂D).

We know that I stands for Infected, U stands for Uninfected, D for Infection detected, N for infection no detected.

Then, a true positive will be given by the intersection of Infected and Infection Detected.

3 0

3 years ago

Read 2 more answers

A ski resort claims that there is a 75% chance of snow on any given day in january and that snowfall happens independently from

lys-0071 [83]

Using the binomial distribution, it is found that the mean and the standard deviation of variable x are given as follows:

$\mu = 3, \sigma = 0.87$

<h3>What is the binomial probability distribution?</h3>

It is the probability of exactly <u>x successes on n repeated trials, with p probability</u> of a success on each trial.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

In this problem, we have that the parameters are given as follows:

n = 4, p = 0.75.

Hence the mean and the standard deviation are given as follows:

E(X) = np = 4 x 0.75 = 3.

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{4 \times 0.75 \times 0.25} = 0.87$

More can be learned about the binomial distribution at brainly.com/question/24863377

#SPJ1

7 0

1 year ago

For which function is f(x) equal to f^1(x) ( answer choices in picture )

Sonja [21]

Answer:

C. $f(x)=\frac{x+1}{x-1}$

Step-by-step explanation:

Let's find the inverse of each of the given options.

Option A:

$f(x)=\frac{x+6}{x-6}\\y=\frac{x+6}{x-6}$

To find $f^{-1}(x)$ , replace 'x' with 'y' and 'y' with 'x'. This gives,

$x=\frac{y+6}{y-6}$

Rewrite in terms of 'y'. This gives,

$x(y-6)=y+6\\xy-6x=y+6\\xy-y=6x+6\\y=\frac{6x+6}{x-1}$

The given function $y=\frac{6x+6}{x-1}\ne y=\frac{x+6}{x-6}$

So, option A is incorrect.

Option B:

$f(x)=\frac{x+2}{x-2}\\y=\frac{x+2}{x-2}$

To find $f^{-1}(x)$ , replace 'x' with 'y' and 'y' with 'x'. This gives,

$x=\frac{y+2}{y-2}$

Rewrite in terms of 'y'. This gives,

$x(y-2)=y+2\\xy-2x=y+2\\xy-y=2x+2\\y=\frac{2x+2}{x-1}$

The given function $y=\frac{2x+2}{x-1}\ne y=\frac{x+2}{x-2}$

So, option B is incorrect.

Option C:

$f(x)=\frac{x+1}{x-1}\\y=\frac{x+1}{x-1}$

To find $f^{-1}(x)$ , replace 'x' with 'y' and 'y' with 'x'. This gives,

$x=\frac{y+1}{y-1}$

Rewrite in terms of 'y'. This gives,

$x(y-1)=y+1\\xy-x=y+1\\xy-y=x+1\\y=\frac{x+1}{x-1}$

The given function $y=\frac{x+1}{x-1}\ equals\ y=\frac{x+1}{x-1}$

So, option C is correct.

Option D:

$f(x)=\frac{x+5}{x-5}\\y=\frac{x+5}{x-5}$

To find $f^{-1}(x)$ , replace 'x' with 'y' and 'y' with 'x'. This gives,

$x=\frac{y+5}{y-5}$

Rewrite in terms of 'y'. This gives,

$x(y-5)=y+5\\xy-5x=y+5\\xy-y=5x+5\\y=\frac{5x+5}{x-1}$

The given function $y=\frac{5x+5}{x-1}\ne y=\frac{x+6}{x-6}$

So, option D is incorrect.

Therefore, only option C is correct.

7 0

3 years ago