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iragen [17]
4 years ago
8

Determine the number of real solutions each quadratic equation has. y = 12x2 - 9x 4

Mathematics
2 answers:
Lisa [10]4 years ago
7 0
ANSWER

The quadratic function,

y = 12 {x}^{2}  - 9x + 4
has no real roots.


EXPLANATION

We use the discriminant,

D =  {b}^{2}  - 4ac

to determine the nature of the roots of a quadratic equation.


If we compare

y = 12 {x}^{2}  - 9x + 4

to

y = a{x}^{2}   + bx + c



Then

a=12,b=-9,c=4


We substitute these values in to the formula for the discriminant, to obtain,



D =  {( - 9)}^{2}  - 4(12)(4)


D =  81 - 192


This implies that,

D =   - 111 \:  <  \: 0


Since the discriminant is zero, the quadratic function,


y = 12 {x}^{2}  - 9x + 4

has no real roots.
krek1111 [17]4 years ago
3 0
  Find the Vertex of   y = 12x2-9x+4
 <span>  y = 2.313</span>
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Answer:

In basic mathematics, pi is used to find the area and circumference of a circle. Pi is used to find area by multiplying the radius squared times pi. So, in trying to find the area of a circle with a radius of 3 centimeters, π32 = 28.27 cm.

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A circle with radius 4 has a sector with central angle of 8/5pi radians.
Olin [163]

Answer:

(64/5)π units²

Step-by-step explanation:

The area of this sector would be:

Given central angle

------------------------------ *(area of whole circle)

            2π rad

In this case, the area of the sector is:

      (8/5) π rad

------------------------------ * π(4 units)^2

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and this reduces to:

(4/5) * π*16 units²      or  (64/5)π units²

8 0
3 years ago
Fill in the blank. In a drive thru performance study, the average service time for McDonald's is 203.21 seconds with a standard
Alenkasestr [34]

Answer:

5) 203.35

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

The average service time for McDonald's is 203.21 seconds with a standard deviation of 5.67 seconds.

This means that \mu = 203.21, \sigma = 5.67

Sample of 90

This means that n = 90, s = \frac{5.67}{\sqrt{90}} = 0.59767

There is a 51% chance that the average drive-thru service time is less than ________ seconds.

X when Z is in the 51st percentile, that is, has a p-value of 0.51, so X when Z = 0.025.

Z = \frac{X - \mu}{\sigma}

By the Central Limit Theorem

Z = \frac{X - \mu}{s}

0.025 = \frac{X - 203.21}{0.59767}

X - 203.32 = 0.025*0.59767

X = 203.35

203.35 seconds.

3 0
3 years ago
A person on tour has dollar 360 for his daily expenses. If he extends his tour for 4 days, he has to cut down his daily expenses
mash [69]

Answer:

The original duration of the tour = 20 days

Step-by-step explanation:

Solution:

Total expenses for the tour = $360

Let the original tour duration be for x days.

So, for x days the total expense = $360

<em>Thus the daily expense in dollars can be given by</em> = \frac{360}{x}

Tour extension and effect on daily expenses.

The tour is extended by 4 days.

<em>Tour duration now</em> = (x+4) days

On extension, his daily expense is cut by $3

<em>New daily expense in dollars </em>= (\frac{360}{x}-3)

Total expense in dollars can now be given as:  (x+4)(\frac{360}{x}-3)

Simplifying by using distribution (FOIL).

(x.\frac{360}{x})+(x(-3)+(4.\frac{360}{x})+(4(-3))

360-3x+\frac{1440}{x}-12

348-3x+\frac{1440}{x}

We know total expense remains the same which is = $360.

So, we have the equation as:

348-3x+\frac{1440}{x}=360

Multiplying each term with x to remove fractions.

348x-3x^2+1440=360x

Subtracting 348x both sides

348x-348x-3x^2+1440=360x-348x

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Dividing each term with -3.

\frac{-3x^2}{-3}+\frac{1440}{-3}=\frac{12x}{-3}

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Adding 4x both sides.

x^2+4x-480=-4x+4x

x^2+4x-480=0

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For a quadratic equation: ax^2+bx+c=0

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

Plugging in values from the equation we got.

x=\frac{-4\pm\sqrt{(4)^2-4(1)(-480)}}{2(1)}

x=\frac{-4\pm\sqrt{16+1920}}{2}

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x=\frac{-4+44}{2}   and x=\frac{-4-44}{2}

x=\frac{40}{2}   and x=\frac{-48}{2}

∴ x=20           and x=-24

Since number of days cannot be negative, so we take x=20 as the solution for the equation.

Thus, the original duration of the tour = 20 days

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3 years ago
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