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3 years ago

What is the x value for 21x+7y=42

Mathematics

2 answers:

xz_007 [3.2K]3 years ago

6 0

Step-by-step explanation: The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!

Andreyy893 years ago

5 0

The value of X is 1.66 repeated ?

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sharon bought chick-fil-a for $6.40. there is a 5 percent tip. how much money will sharon leaver for a tip? round to the nearest

AleksAgata [21]

Answer:

0.32

Step-by-step explanation:

0.32

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3 years ago

The concentration, in parts per million, of a type of antibiotic in a human's bloodstream after h hours can be modeled by the po

saveliy_v [14]

Answer:

$C(3)=17.69\ ppm$

Step-by-step explanation:

Given:

Given polynomial function is.

$C(h)=-0.09h^{2} +3.5h+8$

Hours $h=3$

We need to find the concentration of the antibiotic after 3 hours.

Solution:

Rewrite the given polynomial function as.

$C(h)=-0.09h^{2} +3.5h+8$

Substitute $h=3$ in given polynomial function.

$C(3)=-0.09(3)^{2} +3.5\times 3+8$

$C(3)=-0.09\times 9+10.5+8$

$C(3)=-0.81+10.5+8$

$C(3)=-0.81+18.5$

$C(3)=17.69\ ppm$

Therefore, the concentration of the antibiotic after 3 hours $C(3)=17.69\ ppm$ .

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4 years ago

Keats Library purchases a number of new books, all in the category of biography; the library does not acquire any other books. W

PtichkaEL [24]

Answer:

$\large \boxed{87.5 \, \%}$

Step-by-step explanation:

Let x = the original number of books

Then 0.375x = the total number of biographies

and 0.20 x = the original number of biographies

$\text{Percent increase} = \dfrac{\text{ New number - Old number }}{\text{Old number }} \times 100\, \%\\\\= \dfrac{0.375x - 0.20x}{0.20x} \times 100\, \% = \dfrac{0.175x}{0.20x} \times 100\, \% = 0.875 \times 100\, \% = \mathbf{87.5 \, \%}\\\\\text{The number of biographies has increased by $\large \boxed{\mathbf{87.5 \, \%}}$}$

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3 years ago

A social scientist wishes to conduct a survey. She plans to ask a yes/no question to a random sample from the U.S. adult populat

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Answer:

The sample proportion from the sample of 900 is more likely to be close to the true population proportion, p.

Step-by-step explanation:

for the first one

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3 years ago

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Giving brainliest please help, and give steps if possible. Im trying to learn this.

Feliz [49]

To find (fg)(x), you must mult. together the two binomial functions f and g:

(fg)(x) = (6-5x)(6x^2+x = 36x^2 + 6x - 30x^3 - 5x^2

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4 years ago