Cramer's rule:
what is [ax] in the system below?

Ax = ⇒ 3rd answer

Step-by-step explanation:

Lets revise the Cramer's rule

- If the system of equation is ax + by = c and dx + ey = f

- A is the matrix represent this system of equation

- The first column has the coefficients of x, and

  the second column has the coefficients of y

∴ A =

- Ax means replace the column of x by the answers of the equation

∴ Ax =

- Ay means replace the column of y by the answers of the equation

∴ Ay =

* Now lets solve the problem

∵ 4x - y = -3 and -2x + y = 5

∴ A =

- Replace the column of x by the answer to get Ax

∴ Ax =

* Ax in the system of equation is

C

Step-by-step explanation:

Edge2021

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.

step-by-step explanation: