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mash [69]
3 years ago
5

What are the zeros of the quadratic function f(x)=2x^2-10x-3

Mathematics
2 answers:
charle [14.2K]3 years ago
5 0
5/2+(1/2)*sqrt(31), 5/2-(1/2)*sqrt(31)
Sholpan [36]3 years ago
3 0
<h2>Answer:</h2>

The zeros of the  quadratic function f(x)=2x^2-10x-3 are:

               x=\dfrac{5+\sqrt{31}}{2}\ ,\ x=\dfrac{5-\sqrt{31}}{2}    

<h2>Step-by-step explanation:</h2>

Zeros of a function are the possible x values of the function for which the function is equal to zero.

i.e.  all those x for which  f(x)=0

We are given a function f(x) by:

   f(x)=2x^2-10x-3

Now, f(x)=0

2x^2-10x-3=0

We know that the solution of the quadratic equation of the type:

       ax^2+bx+c=0 is given by:

x=\dfrac{-b\pm \sqrt{b^2-4ac}}{2a}

Here we have:

a=2, b= -10 and c= -3

Hence, the solution is:

x=\dfrac{-(-10)\pm \sqrt{(-10)^2-4\times 2\times (-3)}}{2\times 2}\\\\\\x=\dfrac{10\pm \sqrt{100+24}}{4}\\\\\\x=\dfrac{10\pm \sqrt{124}}{4}\\\\\\x=\dfrac{10\pm 2\sqrt{31}}{4}\\\\\\x=\dfrac{5\pm \sqrt{31}}{2}    

Hence,

x=\dfrac{5+\sqrt{31}}{2} and x=\dfrac{5-\sqrt{31}}{2}

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A kite is 85 feet high with 100 feet of string let out. What is the angle of elevation of the string with the ground? Please sho
a_sh-v [17]

Answer:

  58°

Step-by-step explanation:

A right triangle can be drawn to model the geometry of the problem. The hypotenuse of the triangle is the length of the string, 100 ft. The side opposite the angle is the height of the kite above the ground, 85 ft.

The mnemonic SOH CAH TOA reminds you of the relationship between sides and angles.

  Sin = Opposite/Hypotenuse

  sin(α) = (85 ft)/(100 ft) = 0.85

The angle whose sine is 0.85 is found using the arcsine (inverse sine) function:

  α = arcsin(0.85) ≈ 58.2°

The angle of elevation is about 58°.

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When using your calculator to find the values of inverse trig functions, make sure it is in <em>degrees</em> mode. Otherwise, you're likely to get the answer in radians (≈ 1.01599 radians).

6 0
3 years ago
Ricardo S. gave 158 baseball cards to Ayden and 45 cards to Conner. He had 42 cards left. how many baseball cards did Ricardo S.
Inessa05 [86]

Answer:

203 ;  245

Step-by-step explanation:

158 + 45= 203

question 2

203+42= 245

3 0
3 years ago
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Two similiar rectangles have corresponding sides in the ratio 10:3. What is the ratio of their areas
lianna [129]

Answer:

Step-by-step explanation:

The ratio of its areas is equal to

Step-by-step explanation:

we know that

If two figures are similar, then the ratio of its areas is equal to the scale factor squared

In this problem the scale factor is equal to the ratio 10:3

Let

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7 0
3 years ago
Simplify. 5 - 2(x - 3)
V125BC [204]
To solve this, we simply need to remember our rules about order of operations. They tell us that first, we should distribute the 2 with the rest of the parentheses.

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5-2x+6
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3 0
3 years ago
An archaeologist uses an accelerator mass spectrometer to find the age of a buried branch. At the 68\%68%68, percent confidence
Komok [63]

Answer:

B. 10000 years old, with a margin of error of 400 years

Step-by-step explanation:

Assuming this complete problem: "12. An archaeologist uses an accelerator mass spectrometer to find the age of a buried branch. At the 68% confidence level, the spectrometer estimates that the branch was 10,000 years old with a following could the spectrometer estimate as the age of the branch at the 95% confidence level?"

The possible options are:

A. 9500 years old, with a margin of error of 500 years

B. 10000 years old, with a margin of error of 400 years

C. 9500 years olds, with a margin of error of 50 years

D. 10000 years old, with a margin of error of 40 year

Solution to the problem

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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".

\bar X represent the sample mean for the sample  

\mu population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size  

The confidence interval for the mean is given by the following formula:

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

The margin of error for this case is given by this formula:

ME= z_{\alpha/2}\frac{\sigma}{\sqrt{n}}

For the first case the confidence was 68% so then \alpha =1-0.68 =0.32 and \alpha/2 =0.16 we can find a critical value on the normal standard distribution that accumulates 0.16 of the area on each tail and this value is z=\pm 0.994, because P(z<-0.944) = 0.16 and P(Z>.944) = 0.16

The margin of error can be expressed like this:

ME = z_{\alpha/2} SE

We can solve for the standard error on this case and we got:

SE = \frac{ME}{z_{\alpha/2}} =\frac{200}{0.994}=201.207

And then for the new confidence interval we need to calculate the new z_{\alpha}. For the first case the confidence was 95% so then \alpha =1-0.95 =0.05 and \alpha/2 =0.025 we can find a critical value on the normal standard distribution that accumulates 0.025 of the area on each tail and this value is z=\pm 1.96, because P(z<-1.96) = 0.025 and P(Z>1.96) = 0.025. So then the new margin of error would be:

ME = z_{\alpha/2} SE = 1.96*201.207=394.366

The estimation for the mean not changes and from the before and new case is 1000 years. So then the best option for this case would be:

B. 10000 years old, with a margin of error of 400 years

And makes sense since a larger confidence interval means a wider interval.

8 0
3 years ago
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