Answer:

Explanation:
the main thing to understand here is that revenue is the amount earned, and profit is that amount subtracted all the costs. here, the revenue is simply how much she charges for each wedding invitation.
so, we would have
as our function, as we have x wedding invitations and 2.5 is the "value" of each invitation. so, for example 10 invitations means she earns $25, but this isn't the profit, just the revenue. profit is found as the difference of revenue and costs.