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2 years ago

Write a simplified expression for the Area of the rectangle below 3x+7 2x-2

Mathematics

1 answer:

zhenek [66]2 years ago

4 0

Answer:

Step-by-step explanation:

Area of the rectangle = (3x + 7)(2x- 2)

= 3x(2x - 2) + 7*(2x - 2)

= 3x*2x - 3x*2 +7*2x - 7*2

= 6x² - 6x + 14x - 14

= 6x² + 8x - 14

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Does 5(20-8)=17 the problem says which statement is true

stich3 [128]

This is false because 20-8 is 12 and 12 times 5 isnt 17

5 0

3 years ago

Read 2 more answers

Jane wants to estimate the proportion of students on her campus who eat cauliflower. After surveying 24 students, she finds 2 w

irina1246 [14]

Answer:

A 95% confidence interval for the proportion of students who eat cauliflower on Jane's campus is [0.012, 0.270].

Step-by-step explanation:

We are given that Jane wants to estimate the proportion of students on her campus who eat cauliflower. After surveying 24 students, she finds 2 who eat cauliflower.

Firstly, the pivotal quantity for finding the confidence interval for the population proportion is given by;

P.Q. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ~ N(0,1)

where, $\hat p$ = sample proportion of students who eat cauliflower

n = sample of students

p = population proportion of students who eat cauliflower

Here for constructing a 95% confidence interval we have used a One-sample z-test for proportions.

So, 95% confidence interval for the population proportion, p is ;

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5% level

of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < ${\hat p-p}$ < $1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.95

P( $\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ < p < $\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ) = 0.95

Now, in Agresti and Coull's method; the sample size and the sample proportion is calculated as;

$n = n + Z^{2}__(\frac{_\alpha}{2})$

n = $24 + 1.96^{2}$ = 27.842

$\hat p = \frac{x+\frac{Z^{2}__(\frac{\alpha}{2}_) }{2} }{n}$ = $\hat p = \frac{2+\frac{1.96^{2} }{2} }{27.842}$ = 0.141

95% confidence interval for p = [ $\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ , $\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }$ ]

= [ $0.141 -1.96 \times {\sqrt{\frac{0.141(1-0.141)}{27.842} } }$ , $0.141 +1.96 \times {\sqrt{\frac{0.141(1-0.141)}{27.842} } }$ ]

= [0.012, 0.270]

Therefore, a 95% confidence interval for the proportion of students who eat cauliflower on Jane's campus [0.012, 0.270].

The interpretation of the above confidence interval is that we are 95% confident that the proportion of students who eat cauliflower on Jane's campus is between 0.012 and 0.270.

7 0

3 years ago

Solve the System of equations using substitution or elimination. Show work. 3x-4y=-31 X+y=6

Nataly_w [17]

Hope this helps I got (-1, 7)

6 0

3 years ago

9^y-3=8 JUST DO IT! PLZ...

aleksley [76]

Hello My Dear Friend!

$9^y-3=8$ 
We move all terms to the left:
 $9^y-3-(8)=0$ 
We add all the numbers together, and all the variables
 $9^y-11=0$ 
We move all terms containing y to the left, all other terms to the right
 $9^y=11$
$y=11/1$
$y=11$

I Hope my answer has come to your Help. Thank you for posting your question here in $Brainly.$ We hope to answer more of your questions and inquiries soon. Have a nice day ahead! :)

$(Ps. Mark As Brainliest IF Helped!)$

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7 0

3 years ago

8. A substance has a half life of 2.347 minutes.

mina [271]

Answer:

a.) 4 half lives have passed

b) 9.388 minutes

Step-by-step explanation:

Formula for exponential growth / decay is given as:

$A=A_0b^{\frac{t}{c}}$

Where $A$ is the final population

$A_0$ is the initial population

$b$ is the growth factor

$c$ is the time taken for the growth 'b'

$t$ is the amount of time

Here, we are given that:

$A$ = 6. 9 grams

$A_0$ = 110.4 grams

$b = \dfrac{1}{2}$

$c = 2.347$ min

To find:

a.) Number of half lives taken for the decay.

b.) Total time in the decay.

Solution:

a.) Number of half lives taken for the decay is nothing but equal to $\frac{t}{c}$ .

Putting the values in the formula, we get:

$6.9=110.4\times \frac{1}2^{\frac{t}{c}}\\\Rightarrow 6.9=110.4\times 0.5^{\frac{t}{c}}\\\Rightarrow 0.0625=0.5^{\frac{t}{c}}\\\Rightarrow \dfrac{t}{c} =4$

Therefore, the answer is:

4 half lives have passed.

b.) Total time of decay. We have to find the value of $t$ here.

From answer of part a.):

$\dfrac{t}{c} =4\\\Rightarrow \dfrac{t}{2.347} =4\\\Rightarrow t =\bold{9.388\ min}$

7 0

3 years ago