100 Points pls help

Simplify. (-2a^7y^4)(4ay^2)

dybincka [34]

Answer:

$-8a^8y^6$

Step-by-step explanation:

<h2>Lesson : Simplifying:</h2><h2></h2><h2></h2>

Given:

$(-2a^7y^4)(4ay^2)$

"Simplifying"

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$(-2a^7y^4)(4ay^2)$

Remove the parenthesis

$-2a^7y^4\cdot \:4ay^2$

Multiply the numbers

$-8a^7ay^4y^2$

Apply the exponent rule

$-8y^4a^{7+1}y^2$

Add the numbers

$-8y^4a^8y^2$

Apply the exponent rule once again

$-8a^8y^{4+2}$

Add the numbers once again

$-8a^8y^6$

5 0

4 years ago

A 60-watt light bulb advertises that it will last 1500 hours. The lifetimes of these light bulbs is approximately normally distr

Ad libitum [116K]

Answer:

The proportion of these light bulbs that will last less than the advertised time is 18.94% or 0.1894

Step-by-step explanation:

The first thing to do here is to calculate the z-score

Mathematically;

z-score = (x - mean)/SD

= (1500-1550)/57 = -50/57 = -0.88

So the proportion we will need to find is;

P( z < -0.88)

We shall use the standard score table for this and our answer from the table is 0.1894 which is same as 18.94%

8 0

3 years ago

10.

Kay [80]

Answer:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

Step-by-step explanation:

Information provided

$\bar X=32.1$ represent the sample mean

$\mu$ population mean

s=2.4 represent the sample standard deviation

n=83 represent the sample size

Confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The degrees of freedom are given by:

$df=n-1=83-1=82$

The Confidence is given by 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , the critical values for this case are:

$\chi^2_{\alpha/2}=62.132$

$\chi^2_{1- \alpha/2}=104.139$

And replacing into the formula for the interval we got:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

3 0

3 years ago

When can you simplify ratios

riadik2000 [5.3K]

Answer:

you can simplify rations just like you simplify fractions. Whenever you are able to evenly divide both parts of the ratio with out changing the equation's answer, you are able to.

for example

if it were 3:6, you can simplify this by dividing these both by 3, leaving you with 1:2.

4 0

3 years ago

Read 2 more answers

Please hurry this is very urgent!!!!About fifty percent of the population of Alaska lives within a 50-miles radius of Anchorage.

STALIN [3.7K]

Answer: divide the big number by 2

Step-by-step explanation: dude it literally tells you the answer almost xD jsut divide the big number by 2

4 0

3 years ago

Read 2 more answers