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3 years ago

Find the vertex of this parabola y=-5x^2-10x-15

Mathematics

2 answers:

Fynjy0 [20]3 years ago

7 0

Answer:(-1,-10)

Step-by-step explanation:

natta225 [31]3 years ago

3 0

Answer:

vertex = (- 1, - 10 )

Step-by-step explanation:

given the equation of a parabola in standard form

y = ax² + bx + c : a ≠ 0

Then the x-coordinate of the vertex is

$x_{vertex}$ = - $\frac{b}{2a}$

y = - 5x² - 10x - 15 is in standard form

with a = - 5, b = - 10 and c = - 15, hence

$x_{vertex}$ = - $\frac{-10}{-10}$ = - 1

substitute x = - 1 into the equation for y

y = - 5(- 1)² - 10(- 1) - 15 = - 5 + 10 - 15 = - 10

vertex = (- 1, - 10 )

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Alexis bought a CD player. She does not remember the price, but she does know that the 5% sales tax came to $4.80. What was the

snow_lady [41]

Answer:

Price of CD player = $96

Step-by-step explanation:

Given:

Sales tax = 5%

Amount of sales tax = $4.80

Find:

Price of CD player

Computation:

Price of CD player = Amount of sales tax / Sales tax

Price of CD player = 4.8 / 5%

Price of CD player = $96

6 0

2 years ago

Evaluate v(x)=12-2x-5 when x=-2,0, and 5 . v(-2)= v(0)= v(5)=

Vaselesa [24]

Step-by-step explanation:

v(-2)= 12-2x(-2)-5

=12+4-5

=16-5

=11

v(0)= 12-2x0-5

= 12-0-5

=12-5

v(5)= 12-2x5-5

= 12-10-5

=12-5

Hope it helps 

6 0

2 years ago

A data mining routine has been applied to a transaction dataset and has classified 88 records as fraudulent (30 correctly so) an

Firlakuza [10]

Answer:

The classification matrix is attached below

Part a

The classification error rate for the records those are truly fraudulent is 65.91%.

Part b

The classification error rate for records that are truly non-fraudulent is 96.64%

Step-by-step explanation:

The classification matrix is obtained as shown below:

The transaction dataset has 30 fraudulent correctly classified records out of 88 records, that is, 30 records are correctly predicted given that an instance is negative.

Also, there would be 88 - 30 = 58 non-fraudulent incorrectly classified records, that is, 58 records are incorrectly predicted given that an instance is positive.

The transaction dataset has 920 non-fraudulent correctly classified records out of 952 records, that is, 920 records are correctly predicted given that an instance is positive.

Also, there would be 952 - 920 = 32 fraudulent incorrectly classified records, that is, 32 records incorrectly predicted given that an instance is negative.

That is,

Predicted value

Active value Fraudulent Non-fraudulent

Fraudlent 30 58

non-fraudulent 32 920

The classification matrix is obtained by using the information related to the transaction data, which is classified into fraudulent records and non-fraudulent records.

The error rate is obtained as shown below:

The error rate is obtained by taking the ratio of $\left( {b + c} \right)(b+c)$ and the total number of records.

The classification matrix is, shown above

The total number of records is, $30 + 58 + 32 + 920 = 1,040$

The error rate is,

$\begin{array}{c}\\{\rm{Error}}\,{\rm{rate}} = \frac{{b + c}}{{{\rm{Total}}}}\\\\ = \frac{{58 + 32}}{{1,040}}\\\\ = \frac{{90}}{{1,040}}\\\\ = 0.0865\\\end{array}$

The percentage is $0.0865 \times 100 = 8.65$

(a)

The classification error rate for the records those are truly fraudulent is obtained by taking the rate ratio of b and $\left( {a + b} \right)(a+b)$ .

The classification error rate for the records those are truly fraudulent is obtained as shown below:

The classification matrix is, shown above and in the attachment

The error rate for truly fraudulent is,

$\begin{array}{c}\\FP = \frac{b}{{a + b}}\\\\ = \frac{{58}}{{30 + 58}}\\\\ = \frac{{58}}{{88}}\\\\ = 0.6591\\\end{array}$

The percentage is, $0.6591 \times 100 = 65.91$

(b)

The classification error rate for records that are truly non-fraudulent is obtained by taking the ratio of d and $\left( {c + d} \right)(c+d)$ .

The classification error rate for records that are truly non-fraudulent is obtained as shown below:

The classification matrix is, shown in the attachment

The error rate for truly non-fraudulent is,

$\begin{array}{c}\\TP = \frac{d}{{c + d}}\\\\ = \frac{{920}}{{32 + 920}}\\\\ = \frac{{920}}{{952}}\\\\ = 0.9664\\\end{array}$

The percentage is, $0.9664 \times 100 = 96.64$

6 0

3 years ago

It is thought that not as many Americans buy presents to celebrate Valentine's Day anymore. A random sample of 40 Americans yiel

evablogger [386]

Answer:

98% confidence interval of the true proportion of all Americans who celebrate Valentine's Day

(0.3672 , 0.7328)

Step-by-step explanation:

Explanation:-

Given Random sample size n =40

Sample proportion

$p = \frac{x}{n} = \frac{22}{40} = 0.55$

98% confidence interval of the true proportion of all Americans who celebrate Valentine's Day

$(p-Z_{\alpha } \sqrt{\frac{pq}{n} } , p + Z_{\alpha } \sqrt{\frac{pq}{n} } )$

The Z-value Z₀.₉₈ = Z₀.₀₂ = 2.326

98% confidence interval of the true proportion of all Americans who celebrate Valentine's Day

$(0.55-2.326\sqrt{\frac{0.55 X0.45}{40} } , 0.55 + 2.326\sqrt{\frac{0.55 X0.45}{40} } )$

( 0.55 - 0.1828 , 0.55 + 0.1828)

(0.3672 , 0.7328)

6 0

3 years ago

Read 2 more answers

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gladu [14]

Answer:

Step-by-step explanation:

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3 years ago