In January, Beatrice opened a savings account which offers her 6% per annum simple interest. At the beginning of July, she closed the account and transferred all the money to a different bank which offers her 9% per annum simple interest. If her new account was earn3 $2.18 more per month than before, find her original investment.

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.