the coefficient of x² is is a negative 0.6, so this function has a maximum value.
the max value of a quadratic function is the value of f(x) when x=-b/2a,
in this case, a=-0.6, b=382
so x=382/1.2=
r(382/1.2)=-0.6(382/1.2)²+382*(382/1.2)
use a calculator: 60801.67 is the number I got.