The cost to rent a rug-cleaning machine from the supermarket is $23 per day. The supermarket charges a check-out fee of $45 for the rental. Tristanne spent $137 to rent the rug-cleaning machine. If d represents the number of days Tristanne rents the machine, which equation can be used to find the value of d? 23 d = 137
23 d + 45 = 137
45 d = 137
45 d + 23 = 137

23d + 45 = 137

Explanation:

Since it is $23 per day, that dollar amount must be associated with a variable that multiples it per day that it is rented. Finally, you need to add the one time $45. This equation can then be used to find how many days it was rented for.

23d + 45 = 137

23d = 92 (Subtract 45 from both sides)

d = 4 (Divide by 23 on both sides)

The rug-cleaning machine was rented for 4 days. You found this using the equation: 23d + 45 = 137

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.