What is the solution to z + 9 = -18

z=-27 *The answer must have negative sign.*

Explanation:

subtraction property of equality is subtracting the same number from both sides of an equation does not change the equation.

a-c=b-c

addition property of equality is adding the same number to both sides of an equation does not change the equation.

a+c=b=c

first, subtract by 9 both sides of an equation.

z+9-9=-18-9

then, simplify by equation.

18+9=27

It change positive to negative sign.

z=-27

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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.

b.-4 units

all you   do is count how many times you move