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Goshia [24]
3 years ago
9

-5x(4x+6)=21 whats the answer

Mathematics
2 answers:
Lana71 [14]3 years ago
8 0

First we must simplify the left side.

-20x² - 30x = 21

We need to move 21 to the left side of the problem, to do that we need to subtract both sides:

-20² - 30x - 21 = 0

Factor -1 out of -20x² - 30x - 21.

So then we have:

- (20x² + 30x + 21) = 0

Our set is: 20x² + 30x + 21 equal to 0 now we must solve for x.

To do that we need to divide.

x = -15 = √195

-----------------------

     20

AysviL [449]3 years ago
4 0
1.) Multiply the parentheses by -5x
2.) Move the constant to the left
3.) Change the signs
4.) Solve the quadratic equation
5.) Evaluate the powers and multiply
6.) Calculate

Answer: No solution
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Nitella [24]

Answer: {5 ± 2√10, 5 - 2√10}

Step-by-step explanation: First isolate the binomial squared by adding 40 to both sides to get (x - 5)² = 40.

Next, square root both sides to get x - 5 = ± √40.

Notice that root of 40 can be broken down to 2√10.

So we have x - 5 = ± 2√10.

To get <em>x</em> by itself, add 5 to both sides to get x = 5 ± 2√10.

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As a matter of form, the number will always come before the

radical term in your answer to these types of problems.

In other words, we use 5 ± 2√10 instead of ± 2√10 + 5.

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3 years ago
Lisa has collected data to find that the number of pages per book on a book shelf has a normal distribution. What is the probabi
r-ruslan [8.4K]

Answer:

15.85%

Step-by-step explanation:

The empirical rule states that:

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When we say 1,2,3 standard deviation of the mean, that is, it is evenly distributed in both sides of the mean. For example:

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Now, we see that 192 - 27 = 165, so this is 1 standard deviation of the mean [mean - 1*standard deviation], so 34% of data fall in that range.

But we want, data that ARE FEWER than 165. So, we use property of normal distribution.

Half of data (50%) is left of mean, of which 34% fall within 1 standard deviation So the remaining would fall fewer than 165.

That is 50 - 34 = 16 - 0.15 = 15.85%

<u><em>Note:</em></u> since 99.7% fall within 3 standard deviation of mean, so 100 - 99.7 = 0.3 which is distributed in both sides, so 0.3/2=0.15 is subtracted

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liubo4ka [24]

Answer:

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agasfer [191]

Answer:

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Step-by-step explanation:

22 + 15 = d - 17

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