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2 years ago

What is the solution to this system of equations?

Mathematics

2 answers:

vovangra [49]2 years ago

7 0

3x + 2y=-10 equation 1

y=-x -4 equation 2

use the substitution method of elimination to get the answer to the question.

*using substitution

substitute equation 2 in one and we get

3x +2(-x-4)=-10

3x- 2x-8=-10

x=-2 and y=-2

Answer:

Anvisha [2.4K]2 years ago

3 0

Answer: Choice A

(-2, -2)

=============================================================

Explanation:

I'll use the substitution method to solve this system.

Replace y in the first equation with -x-4. This is because y = -x-4 is mentioned in the second equation.

So,

3x + 2y = -10

3x + 2( y ) = -10

3x + 2( -x-4 ) = -10 .... substitution

3x - 2x - 8 = -10

x - 8 = -10

x = -10+8

x = -2

Then use this to find y

y = -x-4

y = -(x) - 4

y = -(-2) - 4

y = 2 - 4

y = -2

We have x = -2 and y = -2 pair up together

They form the ordered pair solution (x, y) = (-2, -2)

This shows why Choice A is the answer.

Another way to see this is to graph each equation given using a tool like Desmos. It's a free graphing app.

See below.

The two lines intersect at (-2, -2) which is the solution.

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2) Confidence interval

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On this case the calculated interval is not the given , but let's assume that the confidence interval is given by the statment: "United States Department of Labor find that 95% confidence interval for the proportion of females in the U.S. labor force is .357 to .443."

3) Correct interpretation

a. The margin of error for the true percentage of females in the U.S. labor force is between 35.7% and 44.3%.

False the confidence interval not conclude about the margin of error conclude about the true proportion.

b. We are 95% confident that between 35.5% and 44.3% of the persons in the U.S. labor force is female.

True, the statement report the confidence level and the limits for the margin of error.

c. The percentage of females in the U.S. labro force is between 35.7% and 44.3%.

False, The statement is not correct because not reports the confidence level.

d. All sample of size 500 will yield a percentage of females in the U.S. labor force that falls within 35.7% and 44.3%

False the confidence interval is for the population proportion not just for the samples of size 500

e. None of these.

False, we have an option that is true.

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