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3 years ago

Someone pls help im struggling if you do tysm ! <333 :)

Mathematics

2 answers:

Tju [1.3M]3 years ago

8 0

The answer should be the first one

Allisa [31]3 years ago

4 0

Answer:

everything except -1 will be the answer

Step-by-step explanation:

4n + 13 < 9

n < -1

if n is -1, the answer would be 9(INCORRECT)

if n is -2, the answer would be 5(CORRECT)

if n is -3, the answer would be 1(CORRECT)

if n is -4, the answer would be -3(CORRECT)

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If the height and base length of a square pyramid are each doubled, how does the volume of the pyramid change?

Vikentia [17]

It quadruples. (Multiplies by 4)

5 0

2 years ago

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.2.a. If the distri

zalisa [80]

Answer:

$P(\= X \ge 51 ) =0.0062$

$P(\= X \ge 51 ) = 0$

Step-by-step explanation:

From the question we are told that

The mean value is $\mu = 50$

The standard deviation is $\sigma = 1.2$

Considering question a

The sample size is n = 9

Generally the standard error of the mean is mathematically represented as

$\sigma_x = \frac{\sigma }{\sqrt{n} }$

=> $\sigma_x = \frac{ 1.2 }{\sqrt{9} }$

=> $\sigma_x = 0.4$

Generally the probability that the sample mean hardness for a random sample of 9 pins is at least 51 is mathematically represented as

$P(\= X \ge 51 ) = P( \frac{\= X - \mu }{\sigma_{x}} \ge \frac{51 - 50 }{0.4 } )$

$\frac{\= X -\mu}{\sigma } = Z (The \ standardized \ value\ of \ \= X )$

$P(\= X \ge 51 ) = P( Z \ge 2.5 )$

=> $P(\= X \ge 51 ) =1- P( Z < 2.5 )$

From the z table the area under the normal curve to the left corresponding to 2.5 is

$P( Z < 2.5 ) = 0.99379$

=> $P(\= X \ge 51 ) =1-0.99379$

=> $P(\= X \ge 51 ) =0.0062$

Considering question b

The sample size is n = 40

Generally the standard error of the mean is mathematically represented as

$\sigma_x = \frac{\sigma }{\sqrt{n} }$

=> $\sigma_x = \frac{ 1.2 }{\sqrt{40} }$

=> $\sigma_x = 0.1897$

Generally the (approximate) probability that the sample mean hardness for a random sample of 40 pins is at least 51 is mathematically represented as

$P(\= X \ge 51 ) = P( \frac{\= X - \mu }{\sigma_x} \ge \frac{51 - 50 }{0.1897 } )$

=> $P(\= X \ge 51 ) = P(Z \ge 5.2715 )$

=> $P(\= X \ge 51 ) = 1- P(Z < 5.2715 )$

From the z table the area under the normal curve to the left corresponding to 5.2715 and

=> $P(Z < 5.2715 ) = 1$

$P(\= X \ge 51 ) = 1- 1$

=> $P(\= X \ge 51 ) = 0$

5 0

2 years ago

2.(3x²-5)-5=9<br> Ayuda/help

Viefleur [7K]

Answer:

Step-by-step explanation:

2(3x²-5)-5=9

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6x²-15=9

6x²=9+15

6x²=24

x²=24/6

x²=4

x=2

3 0

2 years ago

Find x on the triangle

algol [13]

This is an equilateral triangle, which means all the sides are the same length. So, the answer is 35. ☺♥

Hope this helps.

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3 years ago

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nalin [4]

Answer:

None of the above.

Step-by-step explanation:

It would come out to be 3r + t.

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3 years ago

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