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docker41 [41]
2 years ago
14

How can you decide which operation to use to solve a problem?

Mathematics
1 answer:
almond37 [142]2 years ago
7 0

Answer:

it you're asking for like an equation like "4x +3 = 15 " then you do the opposite of what the equation is doing. Basically undoing the problem to get back to the roots of it. like for the example i provided you would subtract 3 from both sides, because it was added originally. then you would divide both sides by 4 because originally you were multiplying.

You might be interested in
In triangle KLM, if K is congruent to L, KL = 9x - 40, LM = 7x - 37, & KM = 3x + 23, find x & the measure of each angle.
Dennis_Churaev [7]

Answer: x = 15, ∠K = 45.7°, ∠L = 45.7°, ∠M = 88.6°

<u>Step-by-step explanation:</u>

Since ∠K ≅ ∠L, then ΔKLM is an isoceles triangle with base KL

 KM ≅ LM

3x + 23 = 7x - 37

       23 = 4x - 37

       60 = 4x

        15 = x

KM = LM = 3x + 23

               = 3(15) + 23

               = 45 + 23

               = 68

KL = 9x - 40

    = 9(15) - 40

    = 135 - 40

    = 95

Next, draw a perpendicular bisector KN from K to KL. Thus, N is the midpoint of KL and ΔMNL is a right triangle.

  • Since N is the midpoint of KL and KL = 95, then NL = 47.5
  • Since ∠N is 90°, then NL is adjacent to ∠l and ML is the hypotenuse

Use trig to solve for ∠L (which equals ∠K):

cos ∠L = \frac{adjacent}{hypotenuse}

cos ∠L = \frac{47.5}{68}

      ∠L = cos⁻¹ (\frac{47.5}{68})

      ∠L = 45.7  

Triangle sum Theorem:

∠K + ∠L + ∠M = 180°    

45.7 + 45.7 + ∠M = 180

       91.4     + ∠M = 180

                      ∠M = 88.6

       

7 0
3 years ago
What is the gcf of 3xy and 42xy​
nignag [31]

Since 3 divides 42, 3xy itself is the greatest common factor of 3xy and 42xy.

Answer: 3xy

7 0
3 years ago
What is the chemical formula for the molecule modeled?
adelina 88 [10]
The correct answer is A
8 0
3 years ago
Read 2 more answers
23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r
Nostrana [21]

Answer:

a) p_v =P(Z          

b) Since p_v we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) P(\bar X >90)=1-P(Z

1-P(Z

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}

And if we solve for n we got:

n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3

Step-by-step explanation:

Previous concepts  and data given  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

We can calculate the sample mean and deviation with the following formulas:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}

\bar X=88.96 represent the sample mean    

s=1.011 represent the sample standard deviation  

n=5 represent the sample selected  

\alpha significance level    

State the null and alternative hypotheses.    

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:    

Null hypothesis:\mu \geq 90    

Alternative hypothesis:\mu < 90    

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:    

z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}  (1)    

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".    

Calculate the statistic  

We can replace in formula (1) the info given like this:    

z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907      

Part a

P-value  

First we need to calculate the degrees of freedom given by:

df=n-1=5-1 = 4

Then since is a left tailed test the p value would be:    

p_v =P(Z    

Part b

Since p_v we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

P(\bar X

The best way to solve this problem is using the normal standard distribution and the z score given by:

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

If we apply this formula to our probability we got this:

P(\bar X >90)=1-P(Z

1-P(Z

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}

And if we solve for n we got:

n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3

7 0
3 years ago
Complementary and
chubhunter [2.5K]

Answer:

\boxed{\boxed{\sf x=42\°}}

Step-by-step explanation:

Given the diagram, we can see that ∠PQR and ∠RQS are complementary angles.

*Two angles with measures that add up to 90° are known as Complementary angles.*

Therefore, m∠PQR+m∠RQS=90°

\sf \angle PQR+\angle RQS=90\°

\sf 48+x=90\°

Subtract 48 from both sides:

\sf 48+x-48=90-48

\sf x=42\°

<u>_______________________________</u>

5 0
2 years ago
Read 2 more answers
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