Which of the following equations are true? select all that apply.
a 7+(-7)=14
b -4+9=5
c )=7
d -2-6=-8

answer: get more recipes with 3 magazines for $20! i often use chicken broth instead of water. 3 tablespoons butter, divided; 1/2 cup freshly grated parmigiano-reggiano bring water and salt to a boil in a large saucepan; pour polenta slowly into 5 minutes to thicken; stir and taste for salt before transferring to a serving bowl.

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.