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3 years ago

Twice a number, added to seven, is the same

Mathematics

1 answer:

eduard3 years ago

6 0

Answer:

Your number is -10

Hope this helps :)

Step-by-step explanation:

Let x be the number

Twice a number is 2x

Added to 7 means + 7 so 2x + 7

Is means =

2x+7=

At this point I have to assume you mean

"is the same as three subtracted from THE SAME number"

Otherwise, rather than a number, we end up with the

equation of a line....

2x + 7 = x - 3 subtract x from both sides

x + 7 = -3 subtract 7 from both sides

x = -10

Your number is -10

Check: 2x+7 = x-3

2(-10) + 7 = -10-3

-20+7 = -13

-13 = -13

The answer fits the parameters of the problem.

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divide the difference by 150:

72/150 = 0.48

Multiply by 100 to get the percent:

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3 years ago

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Answer:

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6 0

3 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

Find an equation of the line that satisfies the given conditions. through (−5, −7); perpendicular to the line passing through (−

murzikaleks [220]

Answer:

The equation would be y = 2x + 3

Step-by-step explanation:

In order to solve this, we first need to find the slope of the line between (-2, 5) and (2, 3). In order to do this, we use the slope formula.

m(slope) = (y2 - y1)/(x2 - x1)

m = (3 - 5)/(2 - -2)

m = -2/4

m = -1/2

Now that we have the original line with a slope of -1/2, we can tell a perpendicular line would have a slope of 2. This is because perpendicular lines have opposite and reciprocal slopes. Now we can use that slope and the given point in point-slope form to get the answer. Be sure to solve for y.

y - y1 = m(x - x1)

y + 7 = 2(x + 5)

y + 7 = 2x + 10

y = 2x + 3

7 0

3 years ago