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aksik [14]
2 years ago
15

Solve the quadratic equations by completing the square. x^2-4x=-1

Mathematics
1 answer:
kkurt [141]2 years ago
8 0

Answer:

2 ± √3

Step-by-step explanation:

<h3>Solving quadratic equation by completing squares:  </h3>

           x² - 4x = -1

  • Divide the coefficient of x by 2.

                 4 ÷ 2 = 2

  •  Now, square the result and add that to both sides of the equation.

          2² = 2* 2 = 4

          x² - 4x + 4 = -1 + 4

          x² - 4x + 4 = 3

         x² - 2 * x * 2 + 2² = 3

  •     Compare it with a² - 2ab + b² . Now , a = x and b = 2

            (x - 2)² = 3

  •     Take square root both sides

             x - 2 = ±√3

                    x = 2 ± √3

<h3>Solutions: x = 2 +√3   ;  2 - √3</h3>
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Help again ASAP...........
Ierofanga [76]
The answer is B and I am certain

Because 2x5 is 10 and 2xr is 2r

So it’s 10+2r
8 0
3 years ago
A student wanted to find the sum of all the even numbers from 1 to 100. He said:
murzikaleks [220]

Answer:

The statements are incorrect as: The sum of even numbers from 1 to 100(i.e. 2550) is not double\twice of the sum of odd numbers from 1 to 100(i.e. 2500).

Step-by-step explanation:

We know that sum of an Arithmetic Progression(A.P.) is given by:

where 'n' denotes the "number" of digits whose sum is to be determined, 'a' denotes the first digit of the series and '' denote last digit of the series.

Now the sum of even numbers i.e. 2+4+6+8+....+100 is given by the use of sum of the arithmetic progression since the series is an A.P. with a common difference of 2.

image with explanation

Hence, sum of even numbers from 1 to 100 is 2550.

Also the series of odd numbers is an A.P. with a common difference of 2.

sum of odd numbers from 1 to 100 is given by: 1+3+5+....+99

.

Hence, the sum of all the odd numbers from 1 to 100 is 2500.

Clearly the sum of even numbers from 1 to 100(i.e. 2550) is not double of the sum of odd numbers from 1 to 100(i.e. 2500).

Hence the statement is incorrect.

Step-by-step explanation:

3 0
3 years ago
Nine tiles are numbered $\color[rgb]{0.35,0.35,0.35}1, 2, 3, \ldots, 9$. Each of three players randomly selects and keeps three
Eduardwww [97]

The probability that all three players obtain an odd sum is 3/14.

<h3>What is probability?</h3>

The probability is the ratio of possible distributions to the total distributions.

I.e.,

Probability = (possible distributions)/(total distributions)

<h3>Calculation:</h3>

Given that,

There are nine tiles - 1, 2, 3,...9, respectively.

A player must have an odd number of odd tiles to get an odd sum. That means he can either have three odd tiles, or two even tiles and an odd tile.

In the given nine tiles the number of odd tiles = 5 and the number of even tiles = 4.

The only possibility is that one player gets 3 odd tiles and the other two players get 2 even tiles and 1 odd tile.

So,

One player can be selected in ^3C_1  ways.

The 3 odd tiles out of 5 can be selected in ^5C_3 ways.

The remaining 2 odd tiles can be selected and distributed in ^2C_1 ways.

The remaining 4 even tiles can be equally distributed in \frac{4 ! \cdot 2 !}{(2 !)^{2} \cdot 2 !} ways.

So, the possible distributions = ^3C_1 × ^5C_3 × ^2C_1 × \frac{4 ! \cdot 2 !}{(2 !)^{2} \cdot 2 !}

⇒ 3 × 10 × 2 × 6 = 360

To find the total distributions,

The first player needs 3 tiles from the 9 tiles in ^9C3=84 ways

The second player needs 3 tiles from the remaining 6 tiles in ^6C_3=20 ways

The third player takes the remaining tiles in 1 way.

So, the total distributions = 84 × 20 × 1 = 1680

Therefore, the required probability = (possible distributions)/(total distributions)

⇒ Probability = 360/1680 = 3/14.

So, the required probability for the three players to obtain an odd sum is 3/14.

Learn more about the probability of distributions here:

brainly.com/question/2500166

#SPJ4

3 0
2 years ago
Students are given 3 minutes to complete each multiple-choice question on a test and 8 minutes for each free-response question.
SpyIntel [72]

Let

x------> the number of multiple choice question

y------> the number of free response question

we know that

3x+8y=55 -----> equation A

x+y=15

x=15-y -----> equation B

Substitute equation B in equation A

3[15-y]+8y=55

45-3y+8y=55

5y=55-45

5y=10

y=2

Find the value of x

x=15-y

x=15-2=13

therefore

<u>the answer is</u>

the number of multiple choice question are 13

the number of free response question are 2

5 0
3 years ago
Read 2 more answers
An airplane descends 1.5 miles to an elevation of 6.05.Find the elevation of the plane befor its descent the intial elevation of
LuckyWell [14K]

Answer:

7.55 miles

Step-by-step explanation:

Given that :

Distance of descent = 1.5 miles

New elevation point after descent = 6.05 miles

The initial elevation of the plane before descent will be :

New elevation point after descent + Distance of descent

(6.05 miles + 1.5 miles)

= 7.55 miles

8 0
3 years ago
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