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3 years ago

Help I do not understand

Mathematics

1 answer:

tamaranim1 [39]3 years ago

5 0

$\bf \begin{cases}
f(x)=\cfrac{x}{x-9}
\\ \quad \\
g(x)=\cfrac{-x}{x-3}
\end{cases}\qquad f(x)+g(x)\implies \cfrac{x}{x-9}+\cfrac{-x}{x-3}$

get their LCD, like you'd with any other fractions, and add them up

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5x + y = -5<br> I need to graph this pls help

Lisa [10]

Hope this helps
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4 0

3 years ago

The yearly sales of candles decreased from 560 to 476. By what percentage did the candle sales decrease?

Korvikt [17]

The candle sales decreases to - 15 percentage.

<u>Step-by-step explanation:</u>

(476 - 560) : 560 x 100

= (476 : 560 - 1)100

= 85 - 100 = - 15

Therefore, - 15% did the candle sales decrease.

4 0

3 years ago

An analyst from an energy research institute in California wishes to precisely estimate a 99% confidence interval of the average

Lena [83]

Answer:

190

Step-by-step explanation:

Data provided in the question:

Confidence level = 99%

Therefore,

α = 1% = 0.01

[ from standard normal table ]

z-value for $z_{\frac{\alpha}{2}}= z_{\frac{0.01}{2}}=$ = 2.58

Margin of error, E = $0.06

Standard deviation, σ = $0.32

Now,

n = $(\frac{z_{0.005}\sigma}{E})^2$

Here,

n is the sample size (or the minimum number of gas stations )

on substituting the respective values, we get

= $(\frac{z_{0.005}\sigma}{E})^2$

= $(\frac{2.58\times0.32}{0.06})^2$

= 13.76²

= 189.3376 ≈ 190

Hence,

minimum number of gas stations that she should include in her sample is 190

5 0

3 years ago

How to isolate scalars from a matrix

I am Lyosha [343]

The technique of matrix isolation involves condensing the substance to be studied with a large excess of inert gas (usually argon or nitrogen) at low temperature to form a rigid solid (the matrix). The early development of matrix isolation spectroscopy was directed primarily to the study of unstable molecules and free radicals. The ability to stabilise reactive species by trapping them in a rigid cage, thus inhibiting intermolecular interaction, is an important feature of matrix isolation. The low temperatures (typically 4-20K) also prevent the occurrence of any process with an activation energy of more than a few kJ mol-1. Apart from the stabilisation of reactive species, matrix isolation affords a number of advantages over more conventional spectroscopic techniques. The isolation of monomelic solute molecules in an inert environment reduces intermolecular interactions, resulting in a sharpening of the solute absorption compared with other condensed phases. The effect is, of course, particularly dramatic for substances that engage in hydrogen bonding. Although the technique was developed to inhibit intermolecular interactions, it has also proved of great value in studying these interactions in molecular complexes formed in matrices at higher concentrations than those required for true isolation.

3 0

3 years ago

The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 247.9 and a standard deviation of

labwork [276]

Answer:

A) Approximate percentage of women with platelet counts within 2 standard deviations of the mean, or between 118.5 and 377.3 = 95%

B) approximate percentage of women with platelet counts between 53.8 and 442.0 = 99.7%

Step-by-step explanation:

We are given;

mean;μ = 247.9

standard deviation;σ = 64.7

A) We want to find the approximate percentage of women with platelet counts within 2 standard deviations of the mean, or between 118.5 and 377.3.

Now, from the image attached, we can see that from the empirical curve, the probability of 1 standard deviation from the mean is (34% + 34%) = 68 %.

While probability of 2 standard deviations from the mean is (13.5% + 34% + 34% + 13.5%) = 95%

Thus, approximate percentage of women with platelet counts within 2 standard deviations of the mean, or between 118.5 and 377.3 = 95%

B) Now, we want to find the approximate percentage of women with platelet counts between 53.8 and 442.0.

53.8 and 442.0 represents 3 standard deviations from the mean.

Let's confirm that.

Since mean;μ = 247.9

standard deviation;σ = 64.7 ;

μ = 247.9

σ = 64.7

μ + 3σ = 247.9 + 3(64.7) = 442

Also;

μ - 3σ = 247.9 - 3(64.7) = 53.8

Again from the empirical curve attached, we cans that at 3 standard deviations from the mean, we have a percentage probability of;

(2.35% + 13.5% + 34% + 34% + 13.5% + 2.35%) = 99.7%

5 0

3 years ago