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3 years ago

8

PLEASE HELP! (Only answer if you know please)

1 answer:

oksano4ka [1.4K]3 years ago

5 0

Answer:

hmm I'm not sure hold up give me a sec

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Jillian is trying to save water, so she reduces the size of her square grass lawn by 8 feet on each side the area of the smaller

horsena [70]

Answer: 20 feet by 20 feet.

Step-by-step explanation:

1. You know that $x$ is the original measure of one side. Since it is a square, all its sides are equal.

2. Therefore, to solve the problem you only need to solve for $x$ , as you can see below:

- You have that:

$(a-b)^{2}=a^{2}-2ab+b^{2}$

- Then, you obtain the following quadratic equation:

$(x-8)^{2} =144\\x^{2}-2(x)(8)+8^{2}=144\\x^{2}-16x-80=0$

- Apply the Quadratic formula to solve it:

$x=\frac{-b+/-\sqrt{b^{2}-4ac}}{2a}\\a=1\\b=-16\\c=-80$

- Then, you obtain:

$x_1=20\\x_2=-4$

3. The dimensions cannot be negative, therefore, the answer is: 20 feet by 20 feet.

3 0

3 years ago

Read 2 more answers

Plz help ill give brainliest

kipiarov [429]

Answer:

243 in^3

Step-by-step explanation:

Cut into 2 rectangles

First one would be ..

12 x 8 = 96

second one would be

7 x 21 = 147

Add them together

147 + 96 = 243

7 0

3 years ago

Which is NOT a major expense category?<br> housing<br> transportation<br> electricity<br> food

ruslelena [56]

That would be food! Hope this hlep!

5 0

3 years ago

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Find the area of the circle. Round your answer to the nearest hundredth. 15 in.

Ede4ka [16]

well nearest hundredth is 3

8 0

3 years ago

Read 2 more answers

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:

a

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

b

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

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

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

So

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

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

5 0

3 years ago