Denny's fruit stall sells oranges for $2 per bag, and he sells pears for $5 per bag. By the end of the day, Denny had made $21. Put this in standard form.

For this problem, we should assign variables to fruits in order.

x = oranges and y = pears

The cost of each fruit times the number of each fruit sold has to equal a grand total of $21

In standard form, this is written as: 2x + 5y = 21