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3 years ago

Describe the first step you would use to solve the equation 2=7y+2-y

Mathematics

1 answer:

madreJ [45]3 years ago

8 0

Solve for ddd.

41 =12d-741=12d−741, equals, 12, d, minus, 7

d =d=d, equals

Hint #11 / 4

Let's add and then divide to get ddd by itself.

Hint #22 / 4

\begin{aligned} 41 &=12d-7 \\ \\ 41\blue{+7} &= 12d-7\blue{+7}~~~~~~\blue{\text{add }7} \text{ to each side}\\ \\ 41\blue{+7}&=12d-\cancel{ 7} {\blue{+}\cancel{\blue{7}}}\\ \\ 41\blue{+7}&=12d\end{aligned}

41+7

=12d−7

=12d−7+7 add 7 to each side

=12d−

=12d

Hint #33 / 4

\begin{aligned}48 &= 12d \\ \\ \dfrac{48}{\pink{12}} &= \dfrac{12d}{\pink{12}} ~~~~~~~\text{divide each side by } \pink{12} \text{ to get } d \text{ by itself }\\ \\ \dfrac{48}{\pink{12}}&=\dfrac{\cancel{12}d}{\cancel{\pink{12}}} \\ \\ \dfrac{48}{\pink{12}}&=d \end{aligned}

=12d

12d

divide each side by 12 to get d by itself

Hint #44 / 4

The answer:

d=\green{4}~~~~~~~~d=4 d, equals, start color green, 4, end color green, space, space, space, space, space, space, space, space[Okay, got it!]

\begin{aligned} 41 &=12d-7 \\\\ 41 &\stackrel{?}{=} 12(\green{4})-7 \\\\ 41 &\stackrel{?}{=} 48-7 \\\\ 41 &= 41 ~~~~~~~~~~\text{Yes!} \end{aligned}

=12d−7

12(4)−7

48−7

=41 Yes!

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A 1980 study was conducted whose purpose was to compare the indoor air quality in offices where smoking was permitted with that

kotegsom [21]

Answer:

The null hypothesis is not rejected.

There is no enough evidence to support the claim that the CO level is lower in non-smoking working areas compared to smoking work areas.

P-value = 0.07.

Step-by-step explanation:

We have to perform a test on the difference of means.

The claim that we want to test is that CO is less present in no-smoking work areas.

Then, the null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2 > 0$

being μ1: mean CO level in smoking work areas, and μ2: mean CO level in no-smoking work areas.

The significance level is assumed to be 0.05.

Smoking areas sample

Sample size n1=40.

Sample mean M1=11.6

Sample standard deviation s1=7.3

No-smoking areas sample

Sample size n2=40

Sample mean M2=6.9

Sample standard deviation s2=2.7

First, we calculate the difference between means:

$M_d=M_1-M_2=11.6-7.3=4.3$

Second, we calculate the standard error for the difference between means:

$s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{7.3^2}{40}+\dfrac{2.7^2}{40}}=\sqrt{\dfrac{53.29+7.29}{40}}=\sqrt{\dfrac{60.58}{40}}\\\\\\s_{M_d}=\sqrt{1.5145}=1.23$

Now, we can calculate the t-statistic:

$t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{4.3-0}{1.23}=3.5$

The degrees of freedom are calculated with the Welch–Satterthwaite equation:

$df=\dfrac{(\dfrac{s_1^2}{n_1}+\dfrac{s_2^2}{n_2})^2}{\dfrac{s_1^4}{n_1(n_1-1)}+\dfrac{s_2^4}{n_2(n_2-1)}} \\\\\\\\df=\dfrac{(\dfrac{7.3^2}{40}+\dfrac{2.7^2}{40})^2}{\dfrac{7.3^4}{40(39)}+\dfrac{2.7^4}{40(39)}} =\dfrac{(\dfrac{53.29}{40}+\dfrac{7.29}{40})^2}{\dfrac{2839.82}{1560}+\dfrac{53.14}{1560}} \\\\\\\\df=\dfrac{1.5145^2}{1.8545}=\dfrac{2.2937}{1.8545}=1.237$

The P-value for this right tail test, with 1.237 degrees of freedom and t=3.5 is:

$P-value=P(t>3.5)=0.07$

The P-value is bigger than the significance level, so the effect is not significant. The null hypothesis is not rejected.

There is no enough evidence to support the claim that the CO level is lower in non-smoking working areas compared to smoking work areas.

8 0

4 years ago

I need help!! Please

Andre45 [30]

I don’t know sorry mannnn

8 0

3 years ago

If JM = 5x – 8 and LM = 2x – 6, which expression represents JL?

Delvig [45]

The green line is LM
The red line is JM
The blue point is at the coordinates (2/3, -14/3)

you'll have to excuse the way my graph looks. my graphing application on my computer is weird