Final answer:
The domain of the relationship between the number of customers (x) and the number of sales (y) Sarah wants to graph is all non-negative real numbers, as the number of customers cannot be negative. It is represented by the interval [0, ∞).
Step-by-step explanation:
Understanding the Domain in Graphs
When Sarah wants to graph the relationship between the number of customers in a day (x) and the number of sales (y) for that day, we are talking about plotting a two-dimensional data plot where x is the independent variable and y is the dependent variable.
The domain of the relationship refers to all the possible values that the independent variable, in this case, the number of customers, can take on.
In Sarah's scenario, if the number of customers can range from 0 to any positive number (as one cannot have negative customers), the domain would be all non-negative real numbers, typically shown as [0, ∞) in interval notation.
Using different (x,y) data pairs, Sarah can plot the points on the graph and if the relationship is linear, it would follow an equation of the form y = mx + b, where m represents the slope and b represents the y-intercept.