-7x - 8y = 9 4x -9y = 22

x=1 and y=−2

Step-by-step explanation:

Multiply the first equation by 9,and multiply the second equation by -8.

9(−7x−8y=9)

−8(4x−9y=22)

Becomes:

−63x−72y=81

−32x+72y=−176

Add these equations to eliminate y:

−95x=−95

Then solve−95x=−95for x:

−95x

−95

=

−95

−95

(Divide both sides by -95)

x=1

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

−7x−8y=9

Substitute1forxin−7x−8y=9:

(−7)(1)−8y=9

−8y−7=9(Simplify both sides of the equation)

−8y−7+7=9+7(Add 7 to both sides)

−8y=16

−8y

−8

=

16

−8

(Divide both sides by -8)

y=−2

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: i'm not sure

step-by-step explanation: