This is a dome shaped parabola due to the negative leading coefficient
the 'x' value of the vertex will be found by - b/2a where b = 9 and a =-3
use this value of 'x' in the equation to find the 'y' value of the vertex which will be the function's maximum value.....
Find the maximum value of the function f(x) = -3x^2 + 9x + 7.
Hello Guest!
The extremes of a function are at the zeros of the 1st derivative of the function.
\(f(x) = -3x^2 + 9x + 7\\ \frac{df(x)}{dx}=-6x+9=0\\ x_{max}=1,5\)
\(y = -3x^2 + 9x + 7\\ y=-3\cdot 1.5^2+9\cdot 1.5+7\)
\(y_{max}=13.75\)
\(P_{max}(1.5,\ 13.75)\)
!