Which number is irrational? <br><br> A. 75 <br><br> B. 5√<br><br> C. 7.356 <br><br> D. -3

Amelie solves the following system of equations.

PIT_PIT [208]

The values of x and y that satisfy this system of equations are 10 and 5 respectively

<h3>Simultaneous equation</h3>

Given the system of equations

x + y = 20

3x - 3y = 30

_____________________

x + y = 20

x - y = 10

Add the equations

2x = 20 + 10

2x = 30

x = 30/2

x = 15

Substitute

x -y = 10

15 - y = 10

y = 5

Hence the values of x and y that satisfy this system of equations are 10 and 5 respectively

Learn more on simultaneous equation here: brainly.com/question/16863577

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3 0

2 years ago

It is said that sufferers of a cold virus experience symptoms for 7 days. However, the amount of time is actually a normally dis

AlexFokin [52]

Answer:

a) 0.18% of cold sufferers experience fewer than 4 days of symptoms

b) 64.40% of cold sufferers experience symptoms for between 7 and 10 days.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 7.5, \sigma = 1.2$

a. What proportion of cold sufferers experience fewer than 4 days of symptoms?

This is the pvalue of Z when X = 4. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{4 - 7.5}{1.2}$

$Z = -2.92$

$Z = -2.92$ has a pvalue of 0.0018.

So 0.18% of cold sufferers experience fewer than 4 days of symptoms.

b. What proportion of cold sufferers experience symptoms for between 7 and 10 days?

This is the pvalue of Z when X = 10 subtracted by the pvalue of Z when X = 7. So

X = 10

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{10 - 7.5}{1.2}$

$Z = 2.08$

$Z = 2.08$ has a pvalue of 0.9812.

X = 7

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{7 - 7.5}{1.2}$

$Z = -0.42$

$Z = -0.42$ has a pvalue of 0.3372.

So 0.9812 - 0.3372 = 0.644 = 64.40% of cold sufferers experience symptoms for between 7 and 10 days.

8 0

3 years ago

F(x)=9 x^{3} +2x^2-5x+4 and g(x)=5x^3-7x+4. What is f(x)-g(x)? Show all of your steps and write your finial answer in factored f

olasank [31]

Answer:

{ -0.5 - √2, 0, -.5 + √2 }

Step-by-step explanation:

Let's rewrite these two functions in a vertical column:

f(x)=9 x^{3} +2x^2-5x+4

-g(x)=5x^3-7x+4

Now combine (through subtraction) like terms, in order of descending powers of x:

f(x) - g(x) = 4x^ 3 + 2x^2 + 2x

Let's do some preliminary factoring here. Factor 2x out of each term, obtaining

f(x) - g(x) = 2x(2x^2 + x + 1)

First setting 2x = 0, we find that x = 0 is one solution.

Applying the quadratic formula to 2x^2 + x + 1, we see that a = 2, b = 1 and c = 1. Then the two roots of this quadratic are:

-1 plus or minus √(1^2 - 4(2)(1) ) -1 ± √(8)

x = ----------------------------------------------- = ---------------

2(1) 2

This simplifies to:

-1 plus or minus √(1^2 - 4(2)(1) ) -1 ± 2√(2)

x = ----------------------------------------------- = ---------------

2(1) 2

Thus, the roots of f(x) - g(x) are { -0.5 - √2, 0, -.5 + √2 }

7 0

3 years ago

20 POINTS!!HELP PLEASE!!! PICTURE IS PROVIDED!!QUESTION 6

creativ13 [48]

Question 6

first multiply the numerator and

denominator by 9+(2)^1/2

Question 7

6 0

3 years ago

2а + 20 = -3а - 5 pls help

sammy [17]

Answer: A= -5

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

Which number is irrational? A. 75 B. 5√ C. 7.356 D. -3