Question 855206
1.Yes, all quadratics have a min or max.
2.{{{df/dx=-6x-18=0}}}
{{{x=-3}}}
The maximum occurs at {{{x=-3}}}
3. {{{f(-3)=-3(-3)^2-18(-3)-31}}}
{{{f(-3)=-27+54-31}}}
{{{f(-3)=-4}}}
.
.
{{{drawing(300,300,-10,4,-10,4,grid(1),circle(-3,-4,0.3),graph(300,300,-10,4,-10,4,-3x^2-18x-31))}}}