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3 years ago

3n^2-5n-6=9 help please!

Mathematics

2 answers:

Luden [163]3 years ago

6 0

Answer:

3n^2 -5n -6 = 9 This is a quadratic Equation.

3n^2 -5n -15 = 0

It is solved with the Quadratic Formula:

n = [-b +-sqr root (b^2 - 4ac)] / 2a

a = 3

b = -5

c= -15

n = [--5 +- sqr root(25 -4*3*-15)] / 6

n = [5 +- sqr root (25 + 180) / 6

n = [5 +-sqr root (205) ] / 6

n = 5 + 14.3178210633 / 6

n1 = 19.3178210633 / 6

n1= 3.2196368439

n2= 5 - 14.3178210633 / 6

n2 = -9.3178210633 / 6

n2 = -1.5529701772

Step-by-step explanation:

velikii [3]3 years ago

5 0

Answer:

n = 5/6 ±√(205/36)

n ≈ -1.55297, 3.21964

Step-by-step explanation:

3n² - 5n - 6 = 9

3(n² - (5/3)n - 2) = 9

(n² - (5/3)n - 2) = 9/3

(n² - (5/3)n ) = 3 + 2

(n² - (5/3)n + (5/6)²) = 5 + (5/6)²

(the added term will always be the square of b/2)

(n - (5/6))² = 5 + 25/36

n - 5/6 = ±√(205/36)

n = 5/6 ±√(205/36)

n ≈ -1.55297, 3.21964

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4 years ago

3 3/4 x = 1 1/4<br> 7/5 x = 7/15<br><br> x has to be the same in both equations.

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Answer:

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Step-by-step explanation:

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3 years ago

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3 years ago

Read 2 more answers

Explain how to use the least common multiple to find 5/9 - 2/15

polet [3.4K]

Because you need to have the same denominators to subtract fractions, you need to find the LCM of 15 and 9. The LCM of 15 and 9 is 45. Because 15 goes into 45 3 times, you multiply 2* 3 to find the numerator. Because 9 goes into 45 5 times, you multiply 5*5 to find the numerator. The new equation is 25/45 - 6/45. The answer is 19/45, which cannot be simplified any further.

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4 years ago

From a sample with nequals24, the mean number of televisions per household is 4 with a standard deviation of 1 television. Usin

Otrada [13]

Answer:

At least 18 of the households have between 2 and 6 televisions.

Step-by-step explanation:

Chebyshev Theorem

The Chebyshev Theorem can also be applied to non-normal distribution. It states that:

At least 75% of the measures are within 2 standard deviations of the mean.

At least 89% of the measures are within 3 standard deviations of the mean.

An in general terms, the percentage of measures within k standard deviations of the mean is given by $100(1 - \frac{1}{k^{2}})$ .

In this question:

Mean = 4

Standard deviation = 1

Percentage of households that have between 2 and 6 televisions.

2 = 4 - 2*1

So 2 is two standard deviations below the mean

6 = 4 + 2*1

So 6 is two standard deviations above the mean

By Chebyshev's Theorem, at least 75% of the measures are within 2 standard deviations of the mean.

Out of 24

0.75*24 = 18

At least 18 of the households have between 2 and 6 televisions.

6 0

3 years ago