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Leya [2.2K]
3 years ago
10

Solve the equations 3x + 5y = 21 -20x + 5y show your work

Mathematics
1 answer:
Digiron [165]3 years ago
8 0

Answer:

x=21/23

Step-by-step explanation:

Solve for x:

3x+5y=21−20x+5y

Add 20x to both sides:

3x+5y+20x=−20x+5y+21+20x

23x+5y=5y+21

Subtract 5y to both sides:

23x+5y+−5y=5y+21+−5y

23x=21

Divide both sides by 23:

x=21/23

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Classify the following random variables as discrete or continuous:X: the number of automobile accidents per year in Virginia. Y
Elena-2011 [213]

Answer:

X: discrete

Y: continuous

M: continuous

N: discrete

P: discrete

Q: continuous

Step-by-step explanation:

First, we have to know the difference between discrete and continuous variables:

  • Discrete variables are those that represent things that are counted, 3 red cars, 2 chickens, etc.. They take positive integer values, {0, 1, 2, ..., n}, being [0, n] the interval from which the variable takes values, that means, there is a finite number of possible values.
  • Continuous variables are those that represent things that are measured, 3.56 km of railway laid, 5.77 l of paint used. They take positive real values, that means that in the interval used for the variable there are infinite possible values.

Now, we classify each variable:

  1. The number of automobile accidents per year in Virginia (X) is a discrete variable, as there can't be half an accident, one counts how many accidents are per year to know X.
  2. The length of time to play 18 holes of golf (Y) is a continuous variable, as it can take 2 hours, or 2.5 hours, or 2 hours, 30 minutes, 2 seconds, one measures how long it took to play 18 holes to know Y.
  3. The amount of milk produced yearly by a particular cow (M) is a continuous variable, as one measures how much milk was produced to know M.
  4. The number of eggs laid each month by a hen (N) is a discrete variable, as one counts how much eggs were laid to know N.
  5. The number of building permits issued each month in a certain city (P) is a discrete variable, as one counts how many permits were issued to know P.
  6. The weight of grain produced per acre (Q) is a continuous variable, as one measures the weight per acre to know Q.
3 0
3 years ago
What are the sides of the triangle? What is the total length of the side of the big square?
sattari [20]

Answer:

The sides of the the triangle is 7. The total of the the triangle is 24.

Step-by-step explanation:

I count how many triangle there is and is 7. I count all of the side of the triangle and it's 24.

4 0
3 years ago
What is the percent increase between 1200 grams and 550 grams
makkiz [27]

Answer:118%


Step-by-step explanation: You would subtract 1200 by 550 and put that answer (118) over 1000 and then that would be your percent 118%.


7 0
3 years ago
Sara buys 3 of the same type of dress, but in different colors. If she spends a total of $80.34, how much does each dress cost?
Musya8 [376]

Answer:

80.34 / 3 = 26.78


5 0
4 years ago
Read 2 more answers
20a+12a-8 simplified
bixtya [17]

That would 32a - 8, Good Luck!

7 0
4 years ago
Read 2 more answers
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