Answer:
121
Step-by-step explanation:
The function is f(x) = -(x+8)(x-14) and to find the vertex, multiply it out and substitute -b/2a.
[tex]f(x) = -(x+8)(x-14)\\f(x) = -(x^2+8x-14x-112)\\f(x) = -(x^2-6x-112)\\f(x) = -x^2+6x+112[/tex]
Here a=1, b=6 and c=112. This means -b/2a = -6/-2= 3.
[tex]f(3) = -(3)^2+6(3)+112 = -9+18+112 = 121[/tex]
