49
Step-by-step explanation:
f(x)=-(x-3)(x+11)
The zeros of the equation are 3 and -11
The vertex is 1/2 way between the two values
(3+-11)/2 = -8/2 = -4
The vertex is at x= -4
We substitute this value into the equation to find the y value
f(x)=-(-4-3)(-4+11)
= -(-7)(7)
=49