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murzikaleks [220]
3 years ago
9

What is the value of the expression below when a = 5? ​ ​ 7a - 4

Mathematics
2 answers:
Zinaida [17]3 years ago
8 0
The answer above is correct 31
Ostrovityanka [42]3 years ago
7 0

Answer:

31

Step-by-step explanation:

You might be interested in
An English professor assigns letter grades on a test according to the following scheme. A: Top 9% of scores B: Scores below the
sergeinik [125]

Answer:

The minimum score required for an A grade is 83.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Mean of 72.3 and a standard deviation of 8.

This means that \mu = 72.3, \sigma = 8

Find the minimum score required for an A grade.

This is the 100 - 9 = 91th percentile, which is X when Z has a pvalue of 0.91, so X when Z = 1.34.

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

1.34 = \frac{X - 72.3}{8}

X - 72.3 = 1.34*8

X = 83

The minimum score required for an A grade is 83.

5 0
3 years ago
Needing help stuck on this.
Verdich [7]

Answer:

71

Step-by-step explanat

3 0
3 years ago
Derivative, by first principle<br><img src="https://tex.z-dn.net/?f=%20%5Ctan%28%20%5Csqrt%7Bx%20%7D%20%29%20" id="TexFormula1"
vampirchik [111]
\displaystyle\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan x}h

Employ a standard trick used in proving the chain rule:

\dfrac{\tan\sqrt{x+h}-\tan x}{\sqrt{x+h}-\sqrt x}\cdot\dfrac{\sqrt{x+h}-\sqrt x}h

The limit of a product is the product of limits, i.e. we can write

\displaystyle\left(\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan x}{\sqrt{x+h}-\sqrt x}\right)\cdot\left(\lim_{h\to0}\frac{\sqrt{x+h}-\sqrt x}h\right)

The rightmost limit is an exercise in differentiating \sqrt x using the definition, which you probably already know is \dfrac1{2\sqrt x}.

For the leftmost limit, we make a substitution y=\sqrt x. Now, if we make a slight change to x by adding a small number h, this propagates a similar small change in y that we'll call h', so that we can set y+h'=\sqrt{x+h}. Then as h\to0, we see that it's also the case that h'\to0 (since we fix y=\sqrt x). So we can write the remaining limit as

\displaystyle\lim_{h\to0}\frac{\tan\sqrt{x+h}-\tan\sqrt x}{\sqrt{x+h}-\sqrt x}=\lim_{h'\to0}\frac{\tan(y+h')-\tan y}{y+h'-y}=\lim_{h'\to0}\frac{\tan(y+h')-\tan y}{h'}

which in turn is the derivative of \tan y, another limit you probably already know how to compute. We'd end up with \sec^2y, or \sec^2\sqrt x.

So we find that

\dfrac{\mathrm d\tan\sqrt x}{\mathrm dx}=\dfrac{\sec^2\sqrt x}{2\sqrt x}
7 0
3 years ago
14. A group of crafters is collecting data on the amount of yarn they use for each scarf knitted. Each person collected 12 piece
fgiga [73]

Answer:

D. There is not enough information to make a conclusion about the population mean.

Step-by-step explanation:

One of the crafters Chris has a sample means of 200. This means that the average amount of yarn Chris used is 200 meters. Yet there is nothing else given about the other crafters, hence it is impossible to draw a conclusion.

5 0
3 years ago
The average commute times for employees of a large company is 32 minutes. The commute time of 10employees are 40, 31, 32, 16, 25
Ira Lisetskai [31]

Given:

40,31,32,16,25,35,22,53,23 and 33.

a)

Sample mean:

\bar{x}=32

Population mean:

\mu=\frac{\Sigma(x_i)}{n}_{}\mu=\frac{40+31+32+16+25+35+22+53+23+33}{10}\mu=\frac{310}{10}\mu=31

b)

\sigma=\sqrt[]{\frac{\Sigma(x-\mu)^2}{n-1}}\sigma=\sqrt[]{\frac{81+0+1+225+36+16+81+484+64+4}{10-1}}\sigma=\sqrt[]{\frac{992}{9}}\sigma=\frac{\sqrt[]{992}}{3}\sigma=10.4987\text{Error}=\pm z\times\frac{\sigma}{\sqrt[]{n}}

z value is not given so taken as 95% on confidence level

z=1.96\text{Error}=\pm1.96\times\frac{10.4987}{\sqrt[]{10}}\text{Error}=\pm6.5072\text{Error}=\pm6.5

4 0
1 year ago
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