First, we gotta write this equation in standard form.
so it is y= -x^2 -3x +11
This eqation has a negative a, we have got ourselves a max, which is at the vertex.
The vertex of this equation is ( -b/ 2a, c -b^2/ 4a). It's kind of confusing writing it here.
Plug this formula in and we get ( 3/-2, 11 -9/-4) => ( -3/2, 53/4)
We are finding the maxium for y, so the answer is 53/4.
idk if im right (i think i am), i only learned this recently im in 9th grade.