An online furniture store sells chairs for $100 each and tables for $700 each. Every day, the store can ship no more than 21 pieces of furniture and must sell a minimum of $3900 worth of chairs and tables. If 14 chairs were sold, determine the minimum number of tables that the the store must sell in order to meet the requirements. If there are no possible solutions, submit an empty answer.

First locate the turning point (vertex) of the graph. which is at the coordinates x=5 and y=9 or (5; 9).to determine whether it's a maximum or mininum value, you have to discern whether the vertex's y-value is the highest value or lowest value the graph can reach. since the vertex's y-value, 9 is the highest value the graph can reach, it will be a maximum.another basic way to determine whether the vertex's value is max or min is to see if the graph is smiling or sad. if it's smiling, the turning point/vertex would be a minimum, while a sad parabola would have a maximum y-value at the vertex.