Solve the proportion 7/5=21/x
(show work/explain how u got it please)

x = 15

Step-by-step explanation:

I am going to use the "butterfly" method for proportions

(there is another type of butterfly method that is different, I am not sure if there is another name for this method, sorry!)

Multiply the:

- top left by the bottom right

-the top right by the bottom left

and then:

- set them equal to each other

So we will multiply 7 by x and 21 by 5 (if this doesn't make sense tell me and I will explain it even more!)

7x = 21 * 5

7x = 105

(Divide both sides by 7) x = 15

Hope this helps, have a nice day! :D <3

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.

i think it would be c

mark brainliest if im right

step-by-step explanation: