Can someone help please ):

A function is a relation that maps elements from one set (the domain, the set of the inputs) into elements from another set (the range, the set of the outputs). Such that each element of the domain can be mapped into only one element of the range.

Now let's analyze the given relations.

1)

Here we can see that the inputs are -3, -1, 1, and 2.

Then the domain (the set of the inputs) is:

D = {-3, -1, 1, 2}

And we can see that the outputs are 0, 2, and 5.

Then the range is:

R = {0, 2, 5}

We also can see that each input is being mapped into only one output, then this relation is a function.

2) In this case the inputs are -2, -3, and 5.

Then the domain is:

D = {-2, -3, 5}

And the outputs are 6, 7, 8

Then the range is:

R = {6, 7, 8}

And we can see that each input is mapped into only one output, then this relation is a function.

3) In this case we can see that the inputs are -4, -2, and 0

Then the domain is:

D = {-4, -2, 0}

And we can see that the outputs are -2, -1, 3, and 4.

Then the range is:

R = {-2, -1, 3, 4}

In this case, we can see that the input -4 is being mapped into two different outputs (3 and -1)

Then this relation is not a function.

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.