Mathematics, 31.07.2019 00:00 elyssa34972

Brainliest + 15 points. ? who's up for the challenge?

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Answer from: xojade

X + y = 5 and y = 3x - 1
x - y = -3 2x + y = 14

Solve using substitution.

First, isolate one variable.

x + y = 5
x = 5 - y

Then, plug its expression into the other equation and solve.

x - y = -3
5 - y - y = -3
5 - 2y = -3
-2y = -8
y = 4

Next, plug your new value into one of the original equations to solve for the second variable.

x + y = 5
x + 4 = 5
x = 1

Finally, check work with substitution.

x + y = 5 => 1 + 4 = 5 <--True
x - y = -3 => 1 - 4 = -3 <--True

Next.

y = 3x - 1
2x + y = 14

2x + y = 14
2x + (3x - 1) = 14
2x + 3x - 1 = 14
5x - 1 = 14
5x = 15
x = 3

y = 3x - 1
y = 3(3) - 1
y = 9 -1
y = 8

y = 3x - 1 => 8 = 3(3) - 1 => 8 = 9 - 1 <--True
2x + y = 14 => 2(3) + 8 = 14 => 6 + 8 = 14 <--True

4.
x = 1
y = 4

5.
x = 3
y = 8

Answer from: Quest

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction: this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology: the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion: the last is the discussion, this can be either by management people or persons who are all interested , etc.

Answer from: Quest

{x = -1/2 , y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer: {x = -1/2 , y = -1

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