Derieving Derivative #3

$\dfrac{dy}{dx} = 6x^2-6x-36$

This is $0$ at $x=3$ , $x=-2$

Take double derivative, you get $12x-6$

this is negative at $x=-2$ ...so $x=-2$ is Maxima.

$y = 2(-2)^2-3(-2)^2 -36(-2) +10 = -16-12+72+10= 82-28 = \boxed{54}$