College Algebra
posted by Abreanna .
The number of Mosquitoes M9x), in millions, in a certain area depends on the June rainfall x, in inches:M(x)=19xx^2. What rainfall produces the maximum number of mosquitos?

Your function M(x) = 19x  x^2 is represented by a parabola which opens downwards
find the x of its vertex, that will be the rainfall which causes the most mosquitoes