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Akimi4 [234]
3 years ago
12

Pls help me i need help

Mathematics
2 answers:
Llana [10]3 years ago
8 0

Answer:

3x was subtracted from the left side, but 3x was subtracted from the right side. The Subtract Property of Equality states that you can subtract the same number from each side and the equation will remain true. But 3x and 3 are not the same number (unless x is 1).

x = -8/5

Step-by-step explanation:

Step 1: Simplify both sides of the equation.

  • (7x+3x)+(21)=5
  • 10x + 21 = 5

Step 2: Subtract 12 from both sides.

  • 10x + 21 - 21 = 5 - 21
  • 10x = -16

Step 3: Divide both sides by 10.

  • \frac{10x}{10} = \frac{-16}{10}
  • x = -\frac{8}{5}
AnnyKZ [126]3 years ago
4 0

9514 1404 393

Answer:

  • 3x
  • 3
  • 1
  • x = -1.6

Step-by-step explanation:

You answer this sort of question by comparing each line to the line above to see what the differences are. In the second line, the term 3x is missing from the left side of the equal sign, and the value 5 has been changed to the value 2 on the right side. The wording of the statement you're to fill in tells you that it should read ...

  <u> 3x </u> was subtracted from the left side, but <u> 3 </u> was subtracted from the right side.

  ... 3x and 3 are not the same number (unless x is <u> 1 </u>.)

__

The correct solution is ...

  7x +21 +3x = 5 . . . . . . given

  10x +21 = 5 . . . . . . . . . collect terms

  10x = -16 . . . . . . . . . . . subtract 21 from both sides

  x = -1.6 . . . . . . . . . . . .  divide both sides by 10

_____

<em>Additional comment</em>

It can often work well to "read ahead" when answering a question or series of questions. The later questions or comments often provide clues that help you understand how to answer the earlier questions.

Here, for example, it becomes clear that 3x and 3 were subtracted from the different sides of the equation. You can find that out simply by reading the rest of the statement you're to fill in. These are the answers to the questions asked in the first part of the statement.

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Step-by-step explanation:

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Alina and Asim share Rs 210 in the ratio 2:5. How much money did each of them get?
slavikrds [6]

Answer:

Step-by-step explanation:

Alina=2x---eq(1)

Asim=5x----eq---(2)

So,we get

2x+5x=210

7x=210

x=30

Now,Putting '30' in eq 1 and eq 2

2*30=60

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5 0
3 years ago
Five times the sum of some number plus 3 is equal to 7 times the number minus 1.
Alexandra [31]
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4 0
3 years ago
A phone manufacturer wants to compete in the touch screen phone market. He understands that the lead product has a battery life
alisha [4.7K]

Answer:

a)

The null hypothesis is H_0: \mu \leq 10

The alternative hypothesis is H_1: \mu > 10

b-1) The value of the test statistic is t = 1.86.

b-2) The p-value is of 0.0348.

Step-by-step explanation:

Question a:

Test if the battery life is more than twice of 5 hours:

Twice of 5 hours = 5*2 = 10 hours.

At the null hypothesis, we test if the battery life is of 10 hours or less, than is:

H_0: \mu \leq 10

At the alternative hypothesis, we test if the battery life is of more than 10 hours, that is:

H_1: \mu > 10

b-1. Calculate the value of the test statistic.

The test statistic is:

We have the standard deviation for the sample, so the t-distribution is used to solve this question

t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}

In which X is the sample mean, \mu is the value tested at the null hypothesis, s is the standard deviation and n is the size of the sample.

10 is tested at the null hypothesis:

This means that \mu = 10

In order to test the claim, a researcher samples 45 units of the new phone and finds that the sample battery life averages 10.5 hours with a sample standard deviation of 1.8 hours.

This means that n = 45, X = 10.5, s = 1.8

Then

t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}

t = \frac{10.5 - 10}{\frac{1.8}{\sqrt{45}}}

t = 1.86

The value of the test statistic is t = 1.86.

b-2. Find the p-value.

Testing if the mean is more than a value, so a right-tailed test.

Sample of 45, so 45 - 1 = 44 degrees of freedom.

Test statistic t = 1.86.

Using a t-distribution calculator, the p-value is of 0.0348.

5 0
2 years ago
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