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Aleks [24]
3 years ago
5

In a set of dominoes, each piece is marked with two numbers, one on each end. the pieces are symmetrical so that the two numbers

are unordered. that is, the combination (2, 6) and (6, 2) are not distinguishable. how many pieces can be formed using the numbers 1, 2, ... , 12?
Mathematics
1 answer:
ki77a [65]3 years ago
8 0

That would be the number of combinations of of 2 from 12 + the number of doubles ( 1 and 1 , 2 and 2 and so on).

= 12C2 + 12

= (12*11)/ 2 + 12

= 66 + 12 = 78 Answer

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FEE
frozen [14]

Answer:

The equations represent the line that is parallel to 3x - 4y = 7 and pass through the point (-4,-2) are:

  • y+2=\frac{3}{4}\left(x+4\right)
  • 3x - 4y = -4

Step-by-step explanation:

The slope-intercept form of the line equation

y = mx+b

where

  • m is the slope
  • b is the y-intercept

Given the line

3x - 4y = 7

writing in the slope-intercept form

4y = 3x - 7

dividing both sides by 4

4y/4 = 3/4x - 7/4

y = 3/4x - 7/4

Now, comparing with the slope-intercept form of the line equation

y = 3/4x - 7/4

The slope of the line m = 3/4

We know that parallel lines have the same slopes.

Therefore, the slope of the parallel line is: 3/4

now we have,

The point (-4, -2)

The slope m of parallel line = 3/4

Given the point-slope form of the line equation

y-y_1=m\left(x-x_1\right)

where m is the slope of the line and (x₁, y₁) is the point

substituting (-4, -2) and m = 3/4 in the point-slope form of line equation

\:y-\left(-2\right)=\frac{3}{4}\left(x-\left(-4\right)\right)

y+2=\frac{3}{4}\left(x+4\right)

Thus, the equation in the point-slope form of the line equation is:

y+2=\frac{3}{4}\left(x+4\right)

Simplifying the equation

y+2=\frac{3}{4}\left(x+4\right)

Subtract 3 from both sides

y+2-2=\frac{3}{4}\left(x+4\right)-2

y=\frac{3}{4}x+1

Multiplying the equation by 4

4y = 3x + 4

3x - 4y = -4

Therefore, the equations represent the line that is parallel to 3x - 4y = 7 and pass through the point (-4,-2) are:

  • y+2=\frac{3}{4}\left(x+4\right)
  • 3x - 4y = -4
7 0
3 years ago
Will somebody please assist me what is 7x3x2+5-3=k
Svetllana [295]
In this case just do it left to right, as multiplication comes before addition/subtraction. So 7x3x2+5-3=21x2+5-3=42+5-3=47-3=44=k.
5 0
3 years ago
Read 2 more answers
Your friend asks you to help him with his snow shoveling business and will pay you 3 pennies for the first job. You agree to hel
ratelena [41]

Total = 3^x, where x is the number of jobs worked.

Let x = 7th job:

Total = 3^7 = 2187 pennies. = $21.87

8 0
3 years ago
Read 2 more answers
Please help Factor completely. Show your work (as much work as possible, including a ​list of factors if
defon

Answer:

1. x =0; x = -7

2. x = -3; x = 10

3. x = -5; x = -4

Step-by-step explanation:

(1). 6x² + 42x = 0

6x (x + 7) = 0

6x = 0. OR. x + 7 = 0

x = 0/6. x = 0 - 7

x = 0. x = -7

x = 0

x = -7

(2). x² - 7x - 30 = 0

The factors here are (3, -10)

x² - 10x + 3x - 30 = 0

x ( x - 10) + 3 ( x - 10) = 0

(x + 3) ( x - 10) = 0

x + 3 = 0 OR. x - 10 = 0

x = 0-3. x = 0 + 10

x = -3. x = 10

x = -3

x = 10

(3). x² + 9x + 20 = 0

The factors are ( 4, 5)

x² + 4x + 5x + 20 = 0

x ( x + 4) + 5 ( x + 4) = 0

(x + 5) (x + 4) = 0

x + 5 = 0 . OR. x + 4 = 0

x = 0-5. x = 0 - 4

x = -5. x = -4

x = -5

x = -4

6 0
3 years ago
Read 2 more answers
Please help with this
timurjin [86]

Answer:

Hey mate.....

Step-by-step explanation:

This is ur answer.....

Step 1 :-

<h2> 18.12</h2><h2>+ <u>93.3</u></h2><h2> 111.42</h2>

Step 2 :-

<h2> 111.42 </h2><h2>- <u>16.7</u></h2><h2> 94.72</h2>

Hope it helps!

Follow me! ;)

4 0
2 years ago
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