All categories

3 years ago

Help! i can’t figure this out!

Mathematics

2 answers:

Lunna [17]3 years ago

8 0

X=36 because 1/3 times 36 equals 12

Vlada [557]3 years ago

6 0

The answer is $x=36$ and I will teach you how to slove for it.

Steps:

$\frac{1}{3}x+9=21 \\ \\\mathrm{Subtract\:}9\mathrm{\:from\:both\:sides} \\\frac{1}{3}x+9-9=21-9 \\ \\\mathrm{Simplify} \\\frac{1}{3}x=12$

So yes you have done everything right up to this point, but you missing a step

$\mathrm{Multiply\:both\:sides\:by\:}3: \\3\cdot \frac{1}{3}x=12\cdot \:3$

All whole numbers that we work with in math are really just $\frac{Any\ Number}{1}$ So we cross multiply 3, aka: $\frac{3}{1}$ by $\frac{1}{3}$

$\frac{3}{1} *\frac{1}{3} = 1$ and also $12*3=36$

Now if we simplify we are just left with $x=36$

If you find anything wrong with my answer just let me know, and I can guarantee that I will come back and rework my math. Thanks! :-)

Ps. Brainiest is always a nice touch

You might be interested in

HELP ME PLESE ,3 I NEED THIS

snow_lady [41]

The measure of arc EF = 146 degrees because its central angle = 146 degrees.

5 0

3 years ago

3. A new process has been developed for applying pho toresist to 125-mm silicon wafers used in manufac turing integrated circu

dlinn [17]

Answer:

The null hypothesis is $H_o : \mu = 13.4000$

The alternative hypothesis is $H_a : \mu \ne 13.4000$

The null hypothesis is rejected

The 99% confidence level is $13.3930 < \mu < 13.3994$

Step-by-step explanation:

From the question we are told that

The sample size is n = 10

The population mean is $\mu = 13.4 000 \ angstroms$

The level of significance is $\alpha = 0.05$

The sample data is

13.3987, 13.3957, 13.3902, 13.4015, 13.4001, 13.3918, 13.3965, 13.3925, 13.3946, and 13.4002

Generally the sample mean is mathematically represented as

$\= x = \frac{13.3987+ 13.3957\cdots +13.4002 }{10}$

=> $\= x = 13.3962$

Generally the sample standard deviation is mathematically represented as

$\sigma = \sqrt{\frac{\sum (x_i - \= x)^2}{n} }$

=> $\sigma = \sqrt{\frac{ (13.3987 - 13.3962)^2 + (13.3987 - 13.3962)^2 + \cdots + (13.3987 -13.4002)^2 }{10} }$

=> $\sigma =0.0039$

The null hypothesis is $H_o : \mu = 13.4000$

The alternative hypothesis is $H_a : \mu \ne 13.4000$

Generally the test statistics is mathematically represented as

$z = \frac{\= x - \mu}{\frac{\sigma}{\sqrt{n} } }$

=> $z = \frac{13.3962 - 13.4000}{\frac{0.0039}{\sqrt{10} } }$

=> $z = 3.08$

Generally the p-value is mathematically represented as

$p-value = 2P( z > 3.08)$

From the z-table $P(z > 3.08)= 0.001035$

$p-value = 2* 0.001035$

$p-value = 0.00207$

So from the obtained value we see that

$p-value < \alpha$

Hence the null hypothesis is rejected

Consider the b question

Given that the confidence level is 99% then the level of significance is

$\alpha = (100 -99)\%$

=> $\alpha = 0.01$

Generally from the normal distribution table critical value of $\frac{\alpha }{2}$ is

$Z_{\frac{\alpha }{2} } = 2.58$

Generally the margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} } * \frac{\sigma}{\sqrt{n} }$

=> $E = 2.58 * \frac{0.0039}{\sqrt{10} }$

=> $E = 0.00318$

Generally the 99% confidence interval is mathematically represented as

$13.3962 - 0.00318 < \mu < 13.3962 + 0.00318$

=> $13.3930 < \mu < 13.3994$

7 0

3 years ago

The owner of an office building is expanding the length and width of a parking lot by the same amount. The lot currently measure

Gnoma [55]

The best and most correct answer among the choices provided by your question is the second choice or letter B "20".

The current area is 120(80)=9600 and he want to expand it by 4400 so that the new area will be 9600+4400=14000

14000=(120+x)(80+x)

14000=9600+200x+x^2

x^2+200x-4400=0

x^2-20x+220x-4400=0

x(x-20)+220(x-20)=0

(x+220)(x-20)=0, since x is an increase it must be greater than zero so

x=20ft

(120+20)(80+20)=14000ft^2

I hope my answer has come to your help. Thank you for posting your question here in Brainly.

4 0

3 years ago

Read 2 more answers

a truck driver needs to drive his load to a destination that is 2760 miles away how many miles on average will he have to drive

vladimir1956 [14]

1 week = 7 days....so 1 week and 1/2 day = 7.5 days

2760 / 7.5 = 368 miles per day <==

6 0

3 years ago

The total stopping distance T for a vehicle is T = 2.5x + 0.5x 2 , where T is in feet and x is the speed in miles per hour. Appr

Kobotan [32]

Answer:

% change in stopping distance = 7.34 %