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2 years ago

What are the solution(s) to the quadratic equation 40 − x2 = 0?

Mathematics

2 answers:

alina1380 [7]2 years ago

8 0

Answer:

$x=+2\sqrt{10}$

$x=-2\sqrt{10}$

Step-by-step explanation:

$40-x^2=0$

To solve for x , subtract 40 from both sides

$-40+40-x^2=0-40$

$-x^2=-40$

Divide both sides by -1

$x^2= 40$

Take square root on both sides

$\sqrt{x^2} =\sqrt{40}$

$x=+-2\sqrt{10}$

The values of x are

$x=+2\sqrt{10}$

$x=-2\sqrt{10}$

Anni [7]2 years ago

4 0

X = 20
First, you move the 40 to the other side.
-2x=-40
Then, you divided -40 by -2.
x= -40/-2
x= 20
x is 20 because the negatives cancel out making it positive.

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An angle passes through the point (-7,-5). What is the compass heading of this angle?

umka21 [38]

To find the angle use arc tan (-5/-7) which simplifies tips arctan(5/7). arc tan is tan to the power -1, which is also called inverse tan. The heading of the angle, if you drew this out on a graph your angle would be in the third quadrant and therefore the heading is south of west.

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2 years ago

Dev has 9 shells. Zoe has 55 shells, Zoe gives some shells to Dev. Now zoe has 3 times as many shells as dev. How many shells do

Goryan [66]

Answer:

number of shells zoe gives to dev = 7

number of shells zoe is left with = 55-7= 48

number of shells dev has = 9+7=16

Step-by-step explanation:

let the initial number of shells that dev has be A, and initial number of shells that zoe has be B.

let the number of shells that zoe gives to dev be x.

after giiving x shells zoe is left with 3 times the number of shell as that of dev.

therefore number of shells with zoe = 3×number of shells with dev.

number of shells with zoe = initial shells - x = 55-x

number of shells with dev = initial shells + number of shells he gets

= 9+x

therefore (55-x)=3×(9+x)

55-x = 27+3x

55-27=3x+x

4x = 28

x= 7

therefore number of shells zoe gives to dev = 7

number of shells zoe is left with = 55-7= 48

number of shells dev has = 9+7=16

6 0

2 years ago

Use Euler's formula to derive the identity. (Note that if a, b, c, d are real numbers, a + bi = c + di means that a = c and b =

storchak [24]

Answer with Step-by-step explanation:

We have to prove that

$sin 2\theta=2sin\theta cos\theta$ by using Euler's formula

Euler's formula : $e^{i\theta}=cos\theta+isin\theta$

$e^{i(2\theta)}=(e^{i\theta})^2$

By using Euler's identity, we get

$cos2\theta+isin2\theta=(cos\theta+isin\theta)^2$

$cos2\theta+isin2\theta=(cos^2\theta-sin^2\theta+2isin\theta cos\theta)$

$(a+b)^2=a^2+b^2+2ab, i^2=-1$

$cos2\theta+isin2\theta=cos2\theta+i(2sin\theta cos\theta)$

$cos2\theta=cos^2\theta-sin^2\theta$

Comparing imaginary part on both sides

Then, we get

$sin2\theta=2sin\theta cos\theta$

Hence, proved.

8 0

2 years ago

Nina has x coins. Clayton has 5 fewer coins than six times the number of coins Nina has. Write an expression for the total numbe

DedPeter [7]

Answer:

7x - 5

Step-by-step explanation:

Let

Nina = x coins

Clayton = 6x - 5 coins

Expression for the total number of coins Nina and Clayton have altogether.

Nina + Clayton

= x + (6x - 5)

= x + 6x - 5

= 7x - 5

The correct answer and expression is 7x - 5

7 0

2 years ago

Read 2 more answers

A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past

Volgvan

Answer: We reject the null hypothesis, and we use Normal distribution for the test.

Step-by-step explanation:

Since we have given that

We claim that

Null hypothesis : $H_0:\mu\geq 50000$

Alternate hypothesis : $H_1:\mu$

There is 5% level of significance.

$\bar{X}=46800\\\\\sigma=9800\\\\n=29$

So, the test statistic would be

$z=\dfrac{\bar{X}-\mu}{\dfrac{\sigma}{\sqrt{n}}}\\\\z=\dfrac{46800-50000}{\dfrac{9800}{\sqrt{29}}}\\\\z=-1.75$

Since alternate hypothesis is left tailed test.

So, p-value = P(z≤-2.31)=0.0401

And the P-value =0.0401 is less than the given level of significance i.e. 5% 0.05.

So, we reject the null hypothesis, and we use Normal distribution for the test.

4 0

2 years ago