Which of the following are properties of a perfect square trinomial?a) the first and third terms must be perfect squares b) neither of the perfect squares can have a minus sign c)if the square terms are a2 and b2 then the other term must be 2ab. d) none of the above is a properties of a perfect square trinomial

The property that defines a perfect square trinomial is that the second term is 2 times the product between the squares of each square term.  

Step-by-step explanation:

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.

answerim :

n

step-by-step explanation:

im not sure but my dad knows