Simplify the expression: –2b + 7 – 2a + 5b – 6a

a. –8a+ 3b +7
b. 8a – 3b + 7
c. –4a + 7b + 7
d. 4a – 3b + 7

A. -8a + 3b + 7

Step-by-step explanation: To answer this we have to combine like terms so we have to things being multiplied by a and two things being multiplied by b so we have to combine those to numbers,

So the first number (-2b) is a negative so when we add it to the positive (5b) we get 3b, (-2b + 5b = 3b)

Now onto the a's, both of them are negative so we can add them together then put the negative sign after them, -2a + -6a = -8b,

Finally we have the 7 but it is still just adding 7 to the equation so from what we just did A. -8a + 3b + 7 is the best answer.

If you need any further instruction or help let me know!

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.