Use the tenth’s theory and herons theory u will get it
To get the vertex of the parabola we proceed as follows;
y=-7(x-4)^2-5
The above can be written as:
y=-7x^2+56x-117
The values of a,b and c are:
a=-7, b=56 and c=-117
x=-b/(2a)
x=-56/(-7*2)=4
but;
y=-7x^2+56x-117
y=-7(4)^2+56(4)-117
y=-5
Thus;
x=4 and y=-5
The vertex will be at point (4,-5)
I suggest reading them over and over again to remember them. I know it sounds annoying, but trust me, it'll pay off.
Answer: The first one is = 27.5
1/3 * 25 * 3.3 = 27.5