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yulyashka [42]
3 years ago
8

Solve the simultaneous equationsX + y = 83x - y = 12X =y =​

Mathematics
2 answers:
Vadim26 [7]3 years ago
8 0

Answer:

y= -6

x=14

Step-by-step explanation:

in attachment

Pavlova-9 [17]3 years ago
3 0

Answer: (5,3)

Step-by-step explanation:

Solve by Addition/Elimination

x + y = 8

3x − y = 12

Add the two equations together to eliminate y from the system.

    x + y = 8

<u>+ 3x −y = 12</u>

  4x      = 20

Divide each term in 4x = 20 by 4.

<u>4x</u>  = <u>20</u>

4      4

Cancel the common factor of 4.

x= 20/4

x = 5

Substitute the value found for x into one of the original equations to solve for y.

  (5) + y = 8

Remove parentheses.

  5 + y = 8

Move all terms not containing y to the right side of the equation.

Subtract 5 from both sides of the equation.

  y = 8 − 5

Subtract 5 from 8.

  y = 3

The solution to the independent system of equations can be represented as a point.

  (5, 3)

The result can be shown in multiple forms.

Point Form:

  (5, 3)

Equation Form:

  x = 5, y = 3

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if it takes anne 1/2 hour to read 2/3 of a chapter. About how long will it take her to read a chapter?​
kolbaska11 [484]

Answer:

45 minutes

Step-by-step explanation:

1/2 hour=30 minutes

2/3 of chapter=30 minutes

1/4 of hour=15 minutes

1/3 of chapter=15 minutes

3/4 of hour=45 minutes

3/3 of chapter=45 minutes

6 0
3 years ago
(4x2 – 6x + 2) + (-5x2 + 6x – 6)
lys-0071 [83]
(4*2-6x+2)+(-5x2+6x-6)
8-6x+2+(-5)*2+6x-6
8-6x+2-10+6x-6
\not 10-6x-\not10+6x-6
-6x+6x-6
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The answer is: -6

3 0
4 years ago
PLEASE HELP! 100 POINTS!
BartSMP [9]

Answer:

Mrs. Etercsid

Step-by-step explanation:

One thing we can do is just multiply the averages by the percents in each class and compare from there.

To get from percentages to decimals, we can divide by 100.

For Mr. Tats:

Homework: 25 % -> 0.25

Participation: 10% -> 0.1

Test: 40% -> 0.4

Final: 0.25 -> 0.25

For Mrs. Etercsid:

Homework: 15% -> 0.15

Participation: 10% -> 0.1

Test: 60% -> 0.6

Final: 15% -> 0.15

We can then multiply the averages by the decimals for each teacher and add them up.

Mr. Tats:

0.25 * 81 + 0.1 * 57 + 0.4 * 93 + 0.25 * 87 = 84.9

Mrs. Etercsid:

0.15 * 81 + 0.1 * 57 + 0.6 * 93 + 0.15 * 87 = 86.7

You would get the higher grade with Mrs. Etercsid

7 0
3 years ago
While researching the cost of school lunches per week across the state, you use a sample size of 45 weekly lunch prices. The sta
Drupady [299]

We assume the lunch prices we observe are drawn from a normal distribution with true mean \mu and standard deviation 0.68 in dollars.


We average n=45 samples to get \bar{x}.


The standard deviation of the average (an experiment where we collect 45 samples and average them) is the square root of n times smaller than than the standard deviation of the individual samples. We'll write


\sigma = 0.68 / \sqrt{45} = 0.101


Our goal is to come up with a confidence interval (a,b) that we can be 90% sure contains \mu.


Our interval takes the form of ( \bar{x} - z \sigma, \bar{x} + z \sigma ) as \bar{x} is our best guess at the middle of the interval. We have to find the z that gives us 90% of the area of the bell in the "middle".


Since we're given the standard deviation of the true distribution we don't need a t distribution or anything like that. n=45 is big enough (more than 30 or so) that we can substitute the normal distribution for the t distribution anyway.


Usually the questioner is nice enough to ask for a 95% confidence interval, which by the 68-95-99.7 rule is plus or minus two sigma. Here it's a bit less; we have to look it up.


With the right table or computer we find z that corresponds to a probability p=.90 the integral of the unit normal from -z to z. Unfortunately these tables come in various flavors and we have to convert the probability to suit. Sometimes that's a one sided probability from zero to z. That would be an area aka probability of 0.45 from 0 to z (the "body") or a probability of 0.05 from z to infinity (the "tail"). Often the table is the integral of the bell from -infinity to positive z, so we'd have to find p=0.95 in that table. We know that the answer would be z=2 if our original p had been 95% so we expect a number a bit less than 2, a smaller number of standard deviations to include a bit less of the probability.


We find z=1.65 in the typical table has p=.95 from -infinity to z. So our 90% confidence interval is


( \bar{x} - 1.65 (.101),  \bar{x} + 1.65 (.101) )


in other words a margin of error of


\pm 1.65(.101) = \pm 0.167 dollars


That's around plus or minus 17 cents.




3 0
3 years ago
Read 2 more answers
40 points a bird drops a stick to the ground from a height of 80ft. the function h = 16t^2 +80 gives the stick approximate heigh
Ira Lisetskai [31]
√ 80/16=t t=0.5590169943749474
4 0
3 years ago
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