For a certain mammal, researchers have determined that the mesiodistal crown length of deciduous mandibular first molars is related to the post conception age of the tooth as l(t) = - .015t^2 + 1.42t - 7.4, where l(t) is the crown length (in millimetres) of the molar t weeks after conception. find the maximum length in mesiodistal crown of mandibular first molars during weeks 30 through 60. the maximum length is mm. (round to three decimal places as needed.)

25% increaseplus i think decrease i only know increase: ((

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.